Next cloud op OMV5. Locally works perfect. But syncing with the client connection refused

So I have a strange issue which I can not seem to resolve myself.

I installed nextcloud on OMV a year ago and have no clue which type of install I did back than, whether docker or directly. I don’t seem to find anywhere where the www-data has been placed. It simply doesn’t appear to be on the disk.

So my issue: nextcloud works and is up and running. So when I access Https:// , I can access and login.

If I try to connect the client from the same computet to same address it says connection refused. Also remotely by a address it refuses to connect. (Port forwarding is 100% not the issue)

Trusted domains is set up correctly.

So I went checking if my Apache2 install is ok. It is ok but can’t run because 80 and 443 are in use . 443 by docker.

What I don’t get is that it works to login by internet locally to nextcloud but not with the client program.

All is update and upgraded on the system.

Second question. How is it possible that nowhere in /var/www/ i have a folder for nextcloud and data? Where could it be than? Because I can access it from a local computer. So I need to have a data folder somewhere right?

I am not a complete noob, but I really don’t understand where the problem might be this time as I can access nextcloud and login to it and all data is correctly in place but I can’t connect by the client app or by duckdns.

Thanks for any help!

Anyone an idea? Or a way how to isolate the problem?