Cannot get my Plex on my NAS to connect on Tmobile home internet

What is the name of the domain?

plexnklj.uk

What is the error number?

just does not work

What is the issue you’re encountering

I switched from Fios to Tmobile Home internet.. dang Gateway does not do port forwarding. looking into the option of Cloudflare. But my Plex is on my Western Dogital PR2100 with OS5 (Locked up version of Debian)Canot get it to work.. can someone please guide me?

What steps have you taken to resolve the issue?

I have installed docker on the PR2100, click configure, open up a webinterface for Portainer.io. cannot move forward.