FIXED
If you have seen this in the login screen of your server…
stdin: is not a tty
…you know the trouble. Well. I've had the exact same problem on my root server. I tried several things to remount /dev/pts
or /dev/tty
but nothing worked and I wasn't able to open a second connection.
Then a friend of mine had the most basic idea to just restart the service "screen", which allows to create multiple virtual console sessions.
Guess what. The command…
service screen restart
…fixed the console sessions to work again. At the time the error occured, we had appox. 20 screens running.
Best Answer
This worked for me:
I believe our server just had too many tty sessions running (which screen sessions actually are) and couln't create a new one. We've had this problem only once before and we had about the same size of screens running.
After finding the bug, we also reinstalled "screen" by typing:
just to make sure it's a setup error. We haven't had any problems since then.
EDIT: I contacted the server hoster to increase the maximum allowed tty sessions (which you should do too). The admin then set the maximum allowed tty sessions from 16 to 2048 (almost unlimited).