Finally, this solved my issue! Thank you so much!
My wife and me were stuck with Client version Nextcloud-3.2.4 and now it is working again.
But i am still concerned that this can not be the most healthy way to do this. Some day this might backfire when every switch i had to flip to make things work start to collide with each other.
Had the same problem like here described, tried every configuration and nothing helped… except a restart of the docker container with the following configuration
So, since I posted this I have now managed to resolve the issue. There were two things I had to do above having the overwriteprotocol and overwrite.cli.url set. I had to remove overwritecondaddr which wasn’t enough on it’s own but a necessary step. My regular setup has a redirect from http to https to enforce the use of https, I had to remove this for the duration of the client installs. Once I was logged in and working then I could re-enable this step. I’m aware that I may have to disable this every time I have to install a new client but at least I’m up and running for now