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

NEVER add any repositories from Debian, because they might contain newer versions of packages compared to UCS, but lack critial patches for UCS to work properly. Fixing this is out-of-scope and we strongly advise you to re-install the system from scratch!

If you miss any packages you know from Debian, you can enabled the unmaintained repository, which provides all other Debian packages except games.

i unfortunately have exactly the same problem