Remote Access. Port forwarding set up. It shows available, I refresh my browser, not available

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 remote access issues. If that doesn’t help fixing the issue, the outcome of the various checks could help to further pin this down.