Unable to access PMS web app on local server




I'd be very grateful if anyone could help me out with an issue I'm having.

I've been running plex media server on my ubuntu server machine without issue for years. I just updated to the latest version (1.13.0) and PMS appears to be running as normal on my server.

However, I'm unable to access the web interface on local network devices and I can't even access it on the actual server itself (via http://localhost:32400/). Very odd. I've tried uninstalling and reinstalling the latest version but it didn't help. I've tried reinstalling an old version I had (0.9) - still no joy.

I'm really not sure what to try next. Any suggestions would be much appreciated.

Many thanks.