What happens if you try it with /web?
Similar threads:
Plex Media Server Website Only XML Code
Local PMS loads XML page over 32400 but fine over plex.tv
Also, look at the Plex documentation. It always has /web when connecting directly to the IP address of the Plex server.
From Quick-Start & Step by Step Guides for Plex Media Server
- Type
http://127.0.0.1:32400/webinto the address bar - Type
http://server.local.ip.address:32400/webinto the address bar (e.g “http://192.168.1.5:32400/web”)