What are these weird permissions? ==> d????????? ? ? ??
When you don't have permission to a folder in Ubuntu (and various other Linux OSs), you will get d?????????.

To recursively fix the permissions, use this command:

chmod -R a+rX matthias


From this answer on Ask Ubuntu:


  To read a file, its read permission needs to be set. However, to read a directory and the listing of its files, both the read and the execute permissions need to be set. If they aren't, you get weird errors like the ones you're experiencing.