Added debian repository to install more tool but no login option


to have a better way to work in the command line i wished to install vim-nox and multitail!
both gave a error
so i did add the debian repository too
apt update
apt install -y vim-nox
apt install -y multitail

both works so far
removed the debian repository and …

i can’t login anymore into the ucs GUI which is giving a error like

Interner Server-Fehler in "".

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/univention/management/console/", line 359, in __error_handling
    six.reraise(etype, exc, etraceback)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/", line 262, in execute
    function.__func__(self, request, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/protocol/", line 980, in handle
  File "/usr/lib/python2.7/dist-packages/univention/management/console/protocol/", line 1001, in _handle_auth
  File "/usr/lib/python2.7/dist-packages/univention/management/console/", line 104, in authenticate
    pam = PamAuth(locale)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/", line 203, in __init__
    self.pam = self.init()
  File "/usr/lib/python2.7/dist-packages/univention/management/console/", line 254, in init
error: ('Kritischer Fehler - sofortiger Abbruch', 26)

doing a apt update give no error and nothing to install too.
is there a way to rescue this ucs or - will i have to set up it again?

have a nice day