I can't create a class

Seems to be a bug when you join modded servers.

You can try just unlocking the classes easy on the C4S server. If you want to do it legit, just delete your profile data and start over.

The C4S community hosts an unlock all server, you can join by IP or looking in the server list.
connect 178.33.157.21:28950 // Server Name: C4S UNLOCK ALL