The indirect connection implies there’s a problem with your remote access setup. That being said… you might want to review your network setup and the container config as for why Plex considers that connection remote in the first place (this can e.g. happen if your container establishes its own subnet inside your home network).
The remote access troubleshooting might be a good starting point.
Check if the new ISP is giving you a publicly routable IPv4 address.
