So I googled the error and checked serverfault, but the solutions didn't fit. Most results were problems with /dev/pts, but that is mounted. Other results are errors with git, but there is no git on the machine.
My account isn't blocked, I can still log in on the console. Other users also have this problem, so I don't think it has something to do with something that's in my .ssh/
I get this response with ssh -vv:
<snip> debug1: Next authentication method: password rogier@server's password: debug2: we sent a password packet, wait for reply debug1: Authentication succeeded (password). debug1: channel 0: new [client-session] debug2: channel 0: send open debug1: Requesting email@example.com debug1: Entering interactive session. debug2: callback start debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug1: Sending env LANG = en_US.UTF-8 debug2: channel 0: request env confirm 0 debug2: channel 0: request shell confirm 1 debug2: fd 3 setting TCP_NODELAY debug2: callback done debug2: channel 0: open confirm rwindow 0 rmax 32768 debug2: channel_input_status_confirm: type 100 id 0 PTY allocation request failed on channel 0 debug2: channel 0: rcvd adjust 2097152 debug2: channel_input_status_confirm: type 99 id 0 debug2: shell request accepted on channel 0
After this the session freezes. Does anyone have any idea what's going on?