So previous your remote connection was fine, but now you can’t connect from outside of your network? Here’s the fix.
add this line in notepad and save the file as plex.bat
netsh interface portproxy add v4tov4 listenport=XXXXX listenaddress=0.0.0.0 connectport=32400 connectaddress=127.0.0.1
Replace XXXXX with the port number you have Plex forwarded to on your router
Run plex.bat as administrator and your problem should be solved. Additionally you can create a windows task to run the task at login. Make sure you select “run with highest privileges” found under “general” in the Task Scheduler library.
Make sure your firewall doesn’t block the process.