Remote Access Intermediate Issue

Hi Everyone

I have an intermediate issue with the remote access to my Plex Media Server. If I restart the server and enable remote access it works for a random amount of time before then showing as inaccessible from outside my network, if I then disable and enable the remote access this does not fix the problem. If I leave it, it will regain remote access by itself, but this then becomes a continuous issue of working or not working and is completely unstable

My firmware is apparently up-to-date, I am running Version 1.2.3.2914

Please help

Thanks

Rich