Certicate mismatch? Plex server 503 error

Plex Media Server Desktops & Laptops
1

Windows 11 (64 bit)
Plex Server 4.132.2 (64 bit)

I am having an issue with my Plex server becoming unreachable after a few minutes.

The error logs show that both localhost:32400 and 127.0.0.1:32400 are unreachable. In Firefox I get 503 errors.

If I restart Plex server it will work for a couple of minutes and then become unreachable.

So far I have:

  • Uninstalled Plex Server (including removing temp folders and Registry Editor entries
  • Changed Plex / Settings / Network / Secure Connections from Required to Preferred (and vice versa)
  • Checked Plex logs for errors (only seeing 127.0.0.1:32400 unreachable errors)

I get the 503 errors when I attempt to access the Plex server using HTTP.

When I use HTTPS instead, I get “Warning: Potential Security Risk Ahead”. So a certificate error.

Anyone know how to fix this?

I suspect it is the certificate issue could be because of a mismatch of the time/date between device/software.

2

Only remotely, or in the local network as well?
If the latter, I’d look out for network equipment/adapters trying to save power by lowering the link-speed of the Ethernet links.
Basically disallow all of these shenanigans in their settings.

If it’s only remotely, then I’d switch to a manual port forwarding, instead of leaving it to Plex to establish a port forwarding automatically. https://support.plex.tv/articles/200931138-troubleshooting-remote-access/

3

The error is happening locally when I double-click the “Plex Server” icon in the taskbar and it attempts to open in the FireFox.

For the few minutes Plex Server works locally, it also works fine remotely (green checkmark in Settings), but once I cannot access it locally, the remote stops working as well.

As far as I can tell it is because the Plex service cannot access localhost or 127.0.0.1.

Edit:
I may have figured out what is causing the issue.

Plex Server is on a remote computer which has a VPN connection enabled.

When I use a remote desktop program to do a local login to my Plex Server, I am getting a warning on the Plex log-in screen with a warning “another user is logging in” showing the Static IP from my ISP.

Maybe since the remote computer is using a VPN connection, it is confused about the concurrent Static IP and VPN addresses, thus creating an invalid certificate.

So far having disabled the VPN on the remote computer seems to have solved the issue. If that did not solve the issue, I will write more.

4

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