Remote access incredibly temperamental

Plex Media Server Remote Access
,
3

Some additional notes…

  1. In Settings → Remote Access, make sure you check the box next to Manually specify public port (it is not visible in your screenshot). That tells Plex to use the manual port and not UPnP.

  2. Some ISP DNS servers have trouble resolving plex.tv domain names. Consider configuring a public DNS such as 1.1.1.1 (Cloudflare), 8.8.8.8 (Google), etc.

  3. From a system on the same network as the Plex server, go to whatismyipaddress.com (or any similar site). The IP address listed should match the public IP address shown in Plex’s remote access settings (86.131…).

  4. Remote Access initially saying “Fully accessible…” then changing after ~1 minute does not mean the system was actually available. That is Plex trying, and then failing, to set up remote access.

  5. Additional Info:
    Troubleshooting Remote Access
    The Basics of Remote Access Troubleshooting