It is possible that some of your issues were due to the plex.tv problems i mentioned earlier here and it appears that I did not the other issue - but you can see reference to it here and here
If there are still issues then they need to be investigated and as a start that would need server logs with debug enabled before last re-launch of Plex Media Server.
So enable debug logging - see https://support.plex.tv/articles/201643703-reporting-issues-with-plex-media-server/
Restart the server anyway to make sure we have fresh logs created and chance of seeing the start up sequence in the logs
Open the Server setting page for remote access and if it is unavailable, take a screenshot - you can mask part of your public IP address (not all of it please) and try a disable - re-enable once and then if it is still not working - click on retry (once)
Wait a couple of minutes and take screenshot as before and downlolad logs zip
See https://support.plex.tv/articles/200250417-plex-media-server-log-files/
Attach logs zip and screenshots and I will have a look
What version did you update from ?
Would like to see logs covering the time when it goes unavailable
see response above on diagnostics
