Plex recently addressed a security breach, requiring users to reset their passwords. After resetting my password successfully on Plex.tv, I encountered an error message when trying to access Plex Media Server on my Synology NAS, saying “Server not authorized.” This issue may affect users with Plex set up on a NAS or a home lab with VLANs. The solution is straightforward once you understand how Plex identifies devices on different subnets as remote connections.
The Issue Post Password Reset
The problem did not lie with the new password but with my network setup. My Plex server runs on a Synology NAS in one VLAN, while most of my devices like Apple TV, phone, and laptop are in a different VLAN. The crucial point is that when Plex asks you to claim a server after a password reset, it recognizes only devices considered local. In this case, “local” doesn’t mean physically nearby but specifically refers to devices on the same subnet. If your device is on a separate VLAN, Plex sees it as a remote connection, similar to accessing from the internet. Therefore, the server denies authorization.
Resolving the “Server Not Authorized” Problem
Once I grasped how Plex works, fixing the issue was simple:
- Move a device to the same VLAN as the Plex server.
- Access the Plex web app directly at: http://IP:32400/web
- The Claim Server option will now be visible on Plex.
- Log in with your new Plex password, and the server will reconnect to your account.
- Move the device back to its original VLAN, and Plex will work correctly.
That’s all it takes. The problem wasn’t Plex forgetting my password but rather Plex’s refusal to validate the claim from what it considered an external network.
Explanation of Plex’s Handling of VLANs as Remote Networks
Plex uses discovery protocols like mDNS/Bonjour for server detection, typically limited to VLANs unless relay or reflection setups are in place. During the reclaim process, Plex relies on this local discovery to confirm the server’s presence on your network. If the client isn’t locally detectable, Plex assumes it’s a remote connection. Although remote access is okay for regular use, Plex doesn’t allow server claims initiated this way, requiring the handshake to be on the same subnet.
Tips for Smooth Plex Operation Across VLANs
For those using Plex on a segmented network, consider these suggestions:
- Enable mDNS/Bonjour reflection or use an mDNS repeater to allow Plex clients to find the server across VLANs.
- Ensure necessary ports are open, including TCP 32400 between VLANs and Plex’s UDP ports for casting and discovery.
- List all subnets in the LAN Networks section in Settings > Network to prevent Plex from labeling your devices as “remote.”
- Alternatively, choose Remote Access if you don’t want to forward discovery traffic between VLANs, though it may introduce additional overhead and transcoding needs.
In Conclusion
The password reset wasn’t the main issue; it highlighted Plex’s treatment of external devices in different subnets as remote entities. For users with Plex on a Synology NAS or any Plex Media Server in VLAN setups, remember this guideline: The initial handshake to reclaim your Plex server must be from the same subnet. Following this practice once will align Plex with your account, enabling smooth streaming within your VLAN setup.