Hello JtotheEvon, I think I have a very similar problem to you.
It started two days ago, I noticed my plex TV app wasn’t able to connect. Then I noticed that my PC app, or accessing via chrome also doesn’t work. Each time I tried signing in to plex.tv it kept throwing back an error, I couldn’t even reset my password. When I’d open Plex locally from my NAS server, it would sign me in with a grey avatar, limited options on the screen, and I wouldn’t be able to access media on my server:
I tried activating my VPN, which then allowed me to see my avatar again, and to sign in to plex.tv and these forums, but I still cannot access my Plex media at all.
I checked the “hosts” folder as mentioned in this thread, but cannot locate any Plex addresses there. I also tried disabling all ad blocks and VPNs but still cannot access my server.
I have made sure to update my plex synology app to the latest version. Any help would be appreciated.
Update: I have managed to fix the issue. I uninstalled plex from my synology NAS, reinstalled it as an “unclaimed” server. Then accessed plex locally. I still had the weird login issue. I then had to activate my VPN, which allowed me to login, and claim the server. Things seem to be working now.
I wonder if your VPN has any type of “kill switch” functionality, and it is subtly breaking your Internet connection … even when the VPN isn’t connected.