I actually got the same issue it seems, but then with build 14.0.3929.1200, another machine with build 14.0.3752.1000 accepts the password.
I thought about this topic because I couldn't uninstall and tested with an older build in the same container thus same password.
I haven't made a ticket about it yet, will probably do this the coming days.
Our password only consists of numbers, lower and uppercase letters, no special characters (15).