While your server is running a check if remote access is working, it’ll display that remote access is up & running. Only when the check is done will the status indicator actually reflect the status of your setup. Thus, with remote access turning red after 30 seconds… consider your remote access not to work at all.
As for the port forward – you only need the TCP forwarding (no UDP).
Did you already have a look at the related troubleshooting support article?
https://support.plex.tv/articles/200931138-troubleshooting-remote-access/
There’s also a guide with some more details on how to troubleshoot what might be causing this issue.
