If you run ' mbs-build submit' from a directory that contains a git repository, but not a module dist-git repostitory, mbs-build prints out json instead of the actual error message:
{
"error": "Forbidden",  
"message": "The submitted scmurl git://pkgs.fedoraproject.org/git@github.com:KarstenHopp/vim?#4fc63505d393451ad3780dc0390cb48587597aaf is not allowed",  
"status": 403
}