Plex gave me a notification about upgrading the agent on my media server. but everytime he fails to upgrade the agent.
The server is on NAS, maybe thats the problem?
remote connection is also disabled.
From the console it says: “Errors in PUT request: Bad Request
400 Bad Request
’agent’ is missing or invalid”
Server Version#: 1.18.6.2350
Player Version#: 4.64.3
I had the same issue on a Synology DSM 7 with plex 1.21.0-3744 (beta), the latest available from the package center.
In the Plex UI (under settings / synology / general) it allowed me to download a new version with PlexMediaServer-1.24.1.4931-1a38e63c6-x86_64_DSM7.spk.
Installing it manually from the NAS fixed the “problem upgrading the library” error.