Whole domain slowly dying

Message of the Day:

Cron <root@mail> /usr/sbin/jitter 600 /usr/lib/univention-server/server_password_change
Pending listener transactions timeout, rolling back with nochange, server password unchanged
univention-app info
UCS: 4.4-8 errata1020
Installed: admindiary-backend=1.0 admindiary-frontend=1.0 cups=2.2.1 dhcp-server=12.0 mobydick=1.0.0 nagios=4.3 pkgdb=11.0 prometheus=1.1-1 prometheus-node-exporter=1.1 samba4=4.10 self-service=4.0 self-service-backend=4.0 4.3/admin-dashboard=1.2

It looks like somthing serious is broken in Master-Backup communication as already mentioned in my unanswered other Post: Interner Server-Fehler in "udm/containers (users/user)"

As i can not find any useful hints for those error-Messages i really would be very happy for some hints to fix those Problems.