The server is up and the app centre WAS working
 (it allowed the install of the takeover app)

However during installs of apps now, it is throwing this error.

no idea how to fix it


Internal server error during "appcenter/query".
Request: appcenter/query

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/univention/management/console/base.py", line 344, in __error_handling
    six.reraise(etype, exc, etraceback)
  File "/usr/lib/python3/dist-packages/six.py", line 693, in reraise
    raise value
  File "/usr/lib/python3/dist-packages/univention/management/console/base.py", line 247, in execute
    function.__func__(self, request, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/decorators.py", line 321, in _response
    result = _multi_response(self, request)
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/decorators.py", line 181, in _response
    return function(self, request)
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/decorators.py", line 443, in _response
    return list(function(self, iterator, *nones))
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/decorators.py", line 289, in _fake_func
    yield function(self, *args)
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/appcenter/__init__.py", line 388, in query
    if not self._test_for_docker_service():
  File "/usr/lib/python3/dist-packages/univention/management/console/modules/appcenter/__init__.py", line 407, in _test_for_docker_service
    if docker_bridge_network_conflict():
  File "/usr/lib/python3/dist-packages/univention/appcenter/utils.py", line 92, in docker_bridge_network_conflict
    my_net = ipaddress.IPv4Network(u'%s/%s' % (iface['network'], iface['netmask']), False)
  File "/usr/lib/python3.7/ipaddress.py", line 1528, in __init__
    addr = self._ip_int_from_string(args[0])
  File "/usr/lib/python3.7/ipaddress.py", line 1135, in _ip_int_from_string
    raise AddressValueError("Expected 4 octets in %r" % ip_str)
ipaddress.AddressValueError: Expected 4 octets in 'None'