I cannot enable remote access, unless the server is restarted. Although NAT is working fine, I also tried manually forwarding port but to no avail. After restarting, remote access worked perfectly, even with auto port selection.
Server Version#: 1.13.9.5456
Player Version#: 3.71.1
Use the manual port forwarding. The automatically created port forwardings often get deleted by routers after a few hours.
Don’t get confused by the red color in the Plex settings. Just verify the functionality of your manual port forwarding with canyouseeme.org (use the ‘external’ port number you have used in your port forwarding).
If it says ‘available’, then all is well.
Let the server run for a few hours - the remote access status display will come around eventually.