I have an Ubuntu Server 18.04.1 with LTSP installed and currently being used with 4 fat clients and 6 users. Each user has the same problem, they cannot log back in after they lock their session. After they enter the password, they get an "invalid password" error.
So far the only solution is to restart the clients, then sign back in.
I have been looking for the last month and a half and can't find anything. Nearly ever thing I've found suggested to deactivate the lock screen all together.
Does anyone know how to fix this issue?
The server doesn't have a desktop environment, but the ltsp clients are using two. Mate and KDE.