title: Passenger repository certificate verification failed
body: <p>I want to install Passenger server on my virtual machine, so I do the following:</p>
  
  <pre><code>sudo sh -c "echo 'deb https://oss-binaries.phusionpassenger.com/apt/passenger trusty main' &gt;&gt; /etc/apt/sources.list.d/passenger.list"
  sudo chown root: /etc/apt/sources.list.d/passenger.list
  sudo chmod 600 /etc/apt/sources.list.d/passenger.list
  </code></pre>
  
  <p>But after I update</p>
  
  <pre><code>sudo apt-get update
  </code></pre>
  
  <p>I get this errors:</p>
  
  <pre><code>Err https://oss-binaries.phusionpassenger.com trusty/main amd64 Packages       
    server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
  Err https://oss-binaries.phusionpassenger.com trusty/main i386 Packages        
    server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
  Ign https://oss-binaries.phusionpassenger.com trusty/main Translation-en_US    
  Ign https://oss-binaries.phusionpassenger.com trusty/main Translation-en       
  Fetched 2,573 kB in 11s (220 kB/s)                                             
  W: Failed to fetch https://oss-binaries.phusionpassenger.com/apt/passenger/dists/trusty/main/binary-amd64/Packages  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
  
  W: Failed to fetch https://oss-binaries.phusionpassenger.com/apt/passenger/dists/trusty/main/binary-i386/Packages  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
  
  E: Some index files failed to download. They have been ignored, or old ones used instead.
  </code></pre>
  
  <p>I already installed it previously many times and had no problems. I have no idea what might go wrong.</p>