Now that I think about it I also can't use the wake on LAN feature of my PC any more so there's something wrong with the internal routing of my devices. The devices are NOT isolated in the Deco app either

  @Wrayman 

Hi, Thank you very much for the feedback.

If the smart TV could still access the Plex server, It's hardly like to be the issue of Deco. Where did you deploy the Plex server, on the PC?

Would there be any error message on the PS5 when it failed to access the Plex server?

As for "use the wake on LAN feature of my PC", do you plan to wake PC over local network only?  Since Deco doesn't support IP&MAC binding, it can't be used for wake over WAN connection.

Best regards.

  @David-TP As I stated in the original post, this all happened shortly after I replaced a broken Deco unit with a new one via RMA so I'm treating it as the likely culprit. All of my devices (PC, Phone, TV) connected to the Plex server on my PC prior to the replacement and the WOL (local only) for my PC worked too, then suddenly stopped. There are also no error messages on the PS5, just unable to connect to my Plex library, but it connects to the internet just fine. I'm going to try connecting the PS5 via WiFi to see if it's an issue with the ports (again) or connecting directly to the Deco instead of the unmanaged switch. That shouldn't be causing issues though as I've tried multiple ports on the switch and once again the TV worked but the PS5 didn't connect to Plex.

Is there any way I can troubleshoot these issues on the Deco? I know I can run off log files in the web interface but I don't have a clue what they mean or what I'm looking for.

  @Wrayman 

Hi, I think we could start with testing the local connection from the PS5 to the PC first(maybe do a ping test first);

Then apart from the Plex server, have you deployed any other system servers on the same PC or any local servers on the TV or other LAN devices? We could also compare other local access from the PS5

Moreover, If you have one more WiFi router, you could temporarily set Deco into AP mode so it no longer deals with any routing request, then check again whether the access to the Plex server works or not on the PS5.

Thank you very much and best regards.