Suddenly cannot connect to my Plex server

[FordGuy61]

@nappuntokki

My main question is do you know how I can reset my Synology DNS Configuration?

In Synology DSM, Control Panel → Network.
General Tab → Manually Configure DNS server.
Suggest using a public DNS, such as 1.1.1.1 (Cloudflare), 8.8.8.8/8.8.4.4 (Google), or 9.9.9.9 (Quad9).

@nappuntokki

Upon launching Plex, I thought that the connection was back but now it does not show my server at all, and I get the button Get Plex Media Server. In settings there is nowhere I can add libraries.

I am using the package center to install Plex, but I do recall a while back I had to do the install manually. So I am wondering if that is my issue now, but enough digressing…

After fixing DNS issues…

Synology FAQ 31: Reset / Reclaim PMS on DSM 7 (Not Authorized - Locked Out)

Uninstall Plex Media Server. After the “are you sure” page, select the “Uninstall Only” (first) option.

Reinstall the same version of Plex Media Server using the Plex Claim Token option. If successful, you will see “Plex Media Server successfully claimed by email address / userid.”