Troubleshooting
From Joban Wiki
Bad connection with server/Severe Network Lag
This would vary between circumstances. However if you were previously able to connect to the server, chances are that it's not your fault.
We currently have an unfortunate issue where at random times a random portion of the player(s) connection will be dropped, causing a huge amount of network lag for them.
There's not a lot we can do at the moment other than to wait out (Or continue playing with the lag), as we rely on external hosting providers for the server which we have no control over.