Bad gateway at some sites

Hi

New at using cloudflare. I’ve setup a tunnel to access my docker servers running at my home. Problem is that some of them don’t run at all.

For example: I have jellyfin.my-domain.com, http, works fine with the correct server ip 192.168.x.x, but if I try a docker container from another server, vikunja.my-domain.com, also http, doesn’t work with the correct ip 192.68.x.x. I also tried the docker name (http://vikunja:1234) with and without port number (both with ip and uri). It gives me an Error code 502: bad gateway and the logs of the cloudflared container (running on the same docker instance) gives me "The service may be down or it may not be responding to traffic from clouflared". I should also point out that the container works when my tailscale vpn is running (so locally it works). What could be the problem here?