I am working on a Linux Mint 16 computer and since recently, every time I want to install something via `apt-get install`, the log message says that the packages couldn't be authenticated. I go ahead and try to install them without authetication and it turns out most of the packages are not found.

At the end of the process, the console message suggests me to use `apt-get update` or `--fix-missing`. So that's what I do:`sudo apt-get update` and immediateley after I try again to install with `sudo apt-get install nginx` but I still get the same message error.

What is the problem? Am I missing something?

Note: I would have copy/pasted the logs but they are in Spanish so they would probably wouldn't have been of much help to most.

UPDATE:
I managed to get the logs in English thanks to @Flup.

Here they are:
For `apt-get install`:

```
ricardo@toshi ~$ sudo apt-get install nginx
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libnet-daemon-perl libplrpc-perl
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  nginx-common nginx-full
The following NEW packages will be installed:
  nginx nginx-common nginx-full
0 upgraded, 3 newly installed, 0 to remove and 17 not upgraded.
Need to get 404 kB of archives.
After this operation, 1246 kB of additional disk space will be used.
Do you want to continue [Y/n]? Y
WARNING: The following packages cannot be authenticated!
  nginx-common nginx-full nginx
Install these packages without verification [y/N]? y
Err http://archive.ubuntu.com/ubuntu/ raring-updates/universe nginx-common all 1.2.6-1ubuntu3.3
  404  Not Found [IP: 91.189.88.153 80]
Err http://security.ubuntu.com/ubuntu/ raring-security/universe nginx-common all 1.2.6-1ubuntu3.3
  404  Not Found [IP: 91.189.92.200 80]
Err http://security.ubuntu.com/ubuntu/ raring-security/universe nginx-full amd64 1.2.6-1ubuntu3.3
  404  Not Found [IP: 91.189.92.200 80]
Err http://security.ubuntu.com/ubuntu/ raring-security/universe nginx all 1.2.6-1ubuntu3.3
  404  Not Found [IP: 91.189.92.200 80]
Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/n/nginx/nginx-common_1.2.6-1ubuntu3.3_all.deb  404  Not Found [IP: 91.189.92.200 80]
Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/n/nginx/nginx-full_1.2.6-1ubuntu3.3_amd64.deb  404  Not Found [IP: 91.189.92.200 80]
Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/n/nginx/nginx_1.2.6-1ubuntu3.3_all.deb  404  Not Found [IP: 91.189.92.200 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

```

For `apt-get update`:

```
ricardo@toshi ~$ sudo apt-get update
Hit http://dl.google.com stable Release.gpg
Ign http://es.archive.ubuntu.com raring Release.gpg                                                                                          
Hit http://archive.canonical.com raring Release.gpg                                                                                          
Hit http://dl.google.com stable Release.gpg                                                                                                  
Hit http://ppa.launchpad.net raring Release.gpg                                                                                              
Ign http://es.archive.ubuntu.com raring Release.gpg                                                                                          
Ign http://archive.ubuntu.com raring Release.gpg                                                                                             
Hit http://dl.google.com stable Release                                                                                                      
Hit http://archive.canonical.com raring Release                                                                                              
Ign http://es.archive.ubuntu.com raring Release                                                                                              
Hit http://ppa.launchpad.net raring Release.gpg                                                                                              
Ign http://archive.ubuntu.com raring-updates Release.gpg                                                                                     
Hit http://dl.google.com stable Release                                                                                                      
Ign http://security.ubuntu.com raring-security Release.gpg                                                                                   
Ign http://es.archive.ubuntu.com raring Release                                                                                              
Hit http://archive.canonical.com raring/partner amd64 Packages                                                                               
Ign http://archive.ubuntu.com raring Release                                                                                                 
Hit http://ppa.launchpad.net raring Release                                                                                                  
Hit http://downloads-distro.mongodb.org dist Release.gpg                                                                                     
Hit http://dl.google.com stable/main amd64 Packages                                                                                          
Get:1 http://packages.linuxmint.com olivia Release.gpg [198 B]                                                                               
Ign http://archive.ubuntu.com raring-updates Release                                                                                         
Hit http://archive.canonical.com raring/partner i386 Packages                                                                                
Hit http://dl.google.com stable/main i386 Packages                                                                                           
Hit http://ppa.launchpad.net raring Release                                                                                                  
Ign http://security.ubuntu.com raring-security Release                                                                                       
Ign http://archive.ubuntu.com raring/main amd64 Packages/DiffIndex                                                                           
Hit http://ppa.launchpad.net raring/main Sources                                                                                             
Ign http://archive.ubuntu.com raring/restricted amd64 Packages/DiffIndex                                                                     
Get:2 http://packages.linuxmint.com olivia Release [18.5 kB]                                                                                 
Hit http://ppa.launchpad.net raring/main amd64 Packages                                                                                      
Ign http://archive.ubuntu.com raring/universe amd64 Packages/DiffIndex                                                                       
Ign http://security.ubuntu.com raring-security/main amd64 Packages/DiffIndex                                                                 
Hit http://dl.google.com stable/main amd64 Packages                                                                                          
Hit http://downloads-distro.mongodb.org dist Release                                                                                         
Ign http://archive.ubuntu.com raring/multiverse amd64 Packages/DiffIndex                                                                     
Hit http://ppa.launchpad.net raring/main i386 Packages                                                                                       
Hit http://dl.google.com stable/main i386 Packages                                                                                           
Ign http://archive.ubuntu.com raring/main i386 Packages/DiffIndex                                                                            
Ign http://security.ubuntu.com raring-security/restricted amd64 Packages/DiffIndex                                                           
Ign http://archive.ubuntu.com raring/restricted i386 Packages/DiffIndex                                                                      
Ign http://archive.ubuntu.com raring/universe i386 Packages/DiffIndex                                                                        
Ign http://security.ubuntu.com raring-security/universe amd64 Packages/DiffIndex                                                             
Ign http://archive.ubuntu.com raring/multiverse i386 Packages/DiffIndex                                                                      
Hit http://toolbelt.heroku.com ./ Release.gpg                                                                                                
Hit http://ppa.launchpad.net raring/main Sources                                                                                             
Get:3 http://packages.linuxmint.com olivia/main amd64 Packages [23.5 kB]                                                                     
Hit http://downloads-distro.mongodb.org dist/10gen amd64 Packages                                                                            
Hit https://get.docker.io docker Release.gpg                                                                                                 
Hit http://ppa.launchpad.net raring/main amd64 Packages                                                                                      
Ign http://security.ubuntu.com raring-security/multiverse amd64 Packages/DiffIndex                                                           
Ign http://archive.canonical.com raring/partner Translation-en                                                                               
Hit http://ppa.launchpad.net raring/main i386 Packages                                                                                       
Hit https://get.docker.io docker Release                                                                                                     
Ign http://archive.canonical.com raring/partner Translation-es                                                                               
Ign http://security.ubuntu.com raring-security/main i386 Packages/DiffIndex                                                                  
Hit http://toolbelt.heroku.com ./ Release                                                                                                    
Hit http://downloads-distro.mongodb.org dist/10gen i386 Packages                                                                             
Hit https://get.docker.io docker/main amd64 Packages                                                                                         
Get:4 http://packages.linuxmint.com olivia/upstream amd64 Packages [9249 B]                                                                  
Ign http://security.ubuntu.com raring-security/restricted i386 Packages/DiffIndex                                                            
Hit https://get.docker.io docker/main i386 Packages                                                                                          
Get:5 http://packages.linuxmint.com olivia/import amd64 Packages [39.2 kB]                                                                   
Ign http://security.ubuntu.com raring-security/universe i386 Packages/DiffIndex                                                              
Hit http://toolbelt.heroku.com ./ Packages                                                                                                   
Ign http://archive.ubuntu.com raring-updates/main amd64 Packages/DiffIndex                                                                   
Ign http://security.ubuntu.com raring-security/multiverse i386 Packages/DiffIndex                                                            
Ign http://archive.ubuntu.com raring-updates/restricted amd64 Packages/DiffIndex                                                             
Ign http://dl.google.com stable/main Translation-en                                                                                          
Ign http://archive.ubuntu.com raring-updates/universe amd64 Packages/DiffIndex                                                               
Ign http://dl.google.com stable/main Translation-es                                                                                          
Ign http://archive.ubuntu.com raring-updates/multiverse amd64 Packages/DiffIndex                                                             
Ign http://dl.google.com stable/main Translation-en                                                                                          
Ign http://archive.ubuntu.com raring-updates/main i386 Packages/DiffIndex                                                                    
Get:6 http://packages.linuxmint.com olivia/main i386 Packages [23.5 kB]                                                                      
Ign http://dl.google.com stable/main Translation-es                                                                                          
Ign http://archive.ubuntu.com raring-updates/restricted i386 Packages/DiffIndex                                                              
Ign http://archive.ubuntu.com raring-updates/universe i386 Packages/DiffIndex                                                                
Ign http://archive.ubuntu.com raring-updates/multiverse i386 Packages/DiffIndex                                                              
Get:7 http://packages.linuxmint.com olivia/upstream i386 Packages [9237 B]                                                                   
Ign http://ppa.launchpad.net raring/main Translation-en                                                                                      
Get:8 http://packages.linuxmint.com olivia/import i386 Packages [40.1 kB]                                                                    
Ign http://ppa.launchpad.net raring/main Translation-es                                                                                      
Ign http://ppa.launchpad.net raring/main Translation-en                                                                                      
Ign http://ppa.launchpad.net raring/main Translation-es                                                                                      
Ign http://toolbelt.heroku.com ./ Translation-en                                                                                             
Ign http://toolbelt.heroku.com ./ Translation-es                                                                                             
Ign http://downloads-distro.mongodb.org dist/10gen Translation-en                                                                            
Ign http://downloads-distro.mongodb.org dist/10gen Translation-es                                                 
Err http://es.archive.ubuntu.com raring/main amd64 Packages                                 
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/universe amd64 Packages                                        
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/main i386 Packages                                             
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/universe i386 Packages        
  404  Not Found [IP: 91.189.92.201 80]
Ign http://es.archive.ubuntu.com raring/main Translation-en           
Ign http://es.archive.ubuntu.com raring/main Translation-es           
Ign http://es.archive.ubuntu.com raring/universe Translation-en       
Ign http://es.archive.ubuntu.com raring/universe Translation-es       
Err http://es.archive.ubuntu.com raring/main amd64 Packages           
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/universe amd64 Packages       
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/main i386 Packages            
  404  Not Found [IP: 91.189.92.201 80]
Err http://es.archive.ubuntu.com raring/universe i386 Packages        
  404  Not Found [IP: 91.189.92.201 80]
Ign http://es.archive.ubuntu.com raring/main Translation-en                                                                                  
Ign http://es.archive.ubuntu.com raring/main Translation-es                                                                                  
Ign http://es.archive.ubuntu.com raring/universe Translation-en                                                                              
Ign http://es.archive.ubuntu.com raring/universe Translation-es                                                                              
Ign http://packages.linuxmint.com olivia/import Translation-en                                                                               
Ign http://packages.linuxmint.com olivia/import Translation-es                                                                               
Ign https://get.docker.io docker/main Translation-en                                                                                         
Ign http://packages.linuxmint.com olivia/main Translation-en                                                                                 
Ign http://packages.linuxmint.com olivia/main Translation-es                                                                                 
Ign http://packages.linuxmint.com olivia/upstream Translation-en                                                                             
Ign https://get.docker.io docker/main Translation-es                                                                                         
Ign http://packages.linuxmint.com olivia/upstream Translation-es                                                                             
Ign http://archive.ubuntu.com raring/main Translation-en                                                                                     
Ign http://archive.ubuntu.com raring/main Translation-es                                                                                     
Ign http://archive.ubuntu.com raring/multiverse Translation-en                                                                               
Ign http://archive.ubuntu.com raring/multiverse Translation-es                                                                               
Ign http://archive.ubuntu.com raring/restricted Translation-en                                                                               
Ign http://archive.ubuntu.com raring/restricted Translation-es                                                                               
Ign http://archive.ubuntu.com raring/universe Translation-en                                                                                 
Ign http://archive.ubuntu.com raring/universe Translation-es                                                                                 
Ign http://archive.ubuntu.com raring-updates/main Translation-en                                                                             
Ign http://archive.ubuntu.com raring-updates/main Translation-es                                                                             
Ign http://archive.ubuntu.com raring-updates/multiverse Translation-en
Ign http://archive.ubuntu.com raring-updates/multiverse Translation-es
Ign http://archive.ubuntu.com raring-updates/restricted Translation-en
Ign http://archive.ubuntu.com raring-updates/restricted Translation-es
Ign http://security.ubuntu.com raring-security/main Translation-en
Ign http://archive.ubuntu.com raring-updates/universe Translation-en
Ign http://archive.ubuntu.com raring-updates/universe Translation-es
Ign http://security.ubuntu.com raring-security/main Translation-es
Err http://archive.ubuntu.com raring/main amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring/restricted amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/multiverse Translation-en
Err http://archive.ubuntu.com raring/universe amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/multiverse Translation-es
Err http://archive.ubuntu.com raring/multiverse amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring/main i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring/restricted i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/restricted Translation-en
Err http://archive.ubuntu.com raring/universe i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring/multiverse i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/restricted Translation-es
Err http://archive.ubuntu.com raring-updates/main amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring-updates/restricted amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/universe Translation-en
Err http://archive.ubuntu.com raring-updates/universe amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring-updates/multiverse amd64 Packages
  404  Not Found [IP: 91.189.92.200 80]
Ign http://security.ubuntu.com raring-security/universe Translation-es
Err http://archive.ubuntu.com raring-updates/main i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring-updates/restricted i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://archive.ubuntu.com raring-updates/universe i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://security.ubuntu.com raring-security/main amd64 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://archive.ubuntu.com raring-updates/multiverse i386 Packages
  404  Not Found [IP: 91.189.92.200 80]
Err http://security.ubuntu.com raring-security/restricted amd64 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/universe amd64 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/multiverse amd64 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/main i386 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/restricted i386 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/universe i386 Packages
  404  Not Found [IP: 91.189.91.15 80]
Err http://security.ubuntu.com raring-security/multiverse i386 Packages
  404  Not Found [IP: 91.189.91.15 80]
Fetched 163 kB in 15s (10.9 kB/s)
W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/universe/a/aufs-tools/aufs-tools_3.0+20120411-3ubuntu1_amd64.deb/dists/raring/main/binary-amd64/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/universe/a/aufs-tools/aufs-tools_3.0+20120411-3ubuntu1_amd64.deb/dists/raring/universe/binary-amd64/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/universe/a/aufs-tools/aufs-tools_3.0+20120411-3ubuntu1_amd64.deb/dists/raring/main/binary-i386/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/universe/a/aufs-tools/aufs-tools_3.0+20120411-3ubuntu1_amd64.deb/dists/raring/universe/binary-i386/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/main/n/nginx/nginx_1.4.6-1ubuntu3_all.deb/dists/raring/main/binary-amd64/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/main/n/nginx/nginx_1.4.6-1ubuntu3_all.deb/dists/raring/universe/binary-amd64/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/main/n/nginx/nginx_1.4.6-1ubuntu3_all.deb/dists/raring/main/binary-i386/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://es.archive.ubuntu.com/ubuntu/pool/main/n/nginx/nginx_1.4.6-1ubuntu3_all.deb/dists/raring/universe/binary-i386/Packages  404  Not Found [IP: 91.189.92.201 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/main/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/restricted/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/universe/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/binary-amd64/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/multiverse/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/main/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/binary-amd64/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/restricted/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/universe/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/binary-amd64/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring/multiverse/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/binary-amd64/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/binary-i386/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/binary-i386/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/binary-i386/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/main/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/binary-i386/Packages  404  Not Found [IP: 91.189.91.15 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/restricted/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/universe/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/multiverse/binary-amd64/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/main/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/restricted/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/universe/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/raring-updates/multiverse/binary-i386/Packages  404  Not Found [IP: 91.189.92.200 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

```