UCS 4.3 Problem with Horde when changing IP

When I change server IP to intranet IP there is a problem to log in to Horde:

Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /horde.

Reason: Error reading from remote server

It takes a long time and usuall ends with an error that the site doesn’t response. Any idea what to check?
Thanks in advance.

I could reproduce the error message on restart of horde (univention-app restart horde), but after some seconds it works again.

But since horde is also a server, based on docker, there might be some extra work, if you change the IP address of the host. The UCR value of “nameserver1” should point to your masters IP address, etc.

root@host:~# univention-app shell horde
root@horde-70481211:/# ucr get nameserver1

Instead of searching and fixing all the needed settings manually, it could be a bit faster to uninstall horde in the App Center and reinstall it afterwards.