Recently purchased Plex Pass Lifetime and sync doesn’t work, it was the main reason why I purchased Plex Pass. The Plex Server is on a NAS DS218+ (DSM version 7.0-41222), Plex version: 4.43.4. In Settings\Sync the server shows the error " The server needs a Plex Pass to use sync.". In my android device (Galaxy Note 10+) I can choose to sync a content, and choose video quality but then nothing happens, says pending and that’s all.
In order to get going on this, I recommend you start with updating your server – from the server version you have provided, the server hasn’t been updated in 2-4 months.
If the server still believes it doesn’t have a Plex Pass to allow it to sync, check if restarting the system (PMS, NAS) gets it to recognize that you have one. That is assuming you don’t have the server setup under a different Plex account?! (just to rule this out as well)
Thanks @tom80H for the reply, I’ve updated the Plex Server and its working now. I used to get a notification when an update was available but since I’m running DSM 7 preview I guess I have to check manually.