Claimed = 0 means the server is still unclaimed.
Are you comfortable using SSH/CLI?
If so, look at: Server credential reset utility for Linux-based platforms
That will definitely claim your Plex Media Server.
I’ve tested it on Synology & Linux, and others have tested it on QNAP.
The link has the details, but the basic are:
a) get a claim token from plex.tv/claim
b) run the script with the claim code.
sudo ./UserCredentialReset.sh claim-xxxxxxx
