Clients not Updating - Unable to copy asset

Hi Community!

I have Xibo installed in Docker on a Linux Server and updated it a few weeks ago from (I believe) version 3.11 to 4.0.6.
This week, I installed a new client and noticed that none of my clients are updating anymore. They are all signed in and authorized, but they have the cloud symbol in the status column.

I checked the player version, and they are running on 1.8 R6.
I updated to 1.8 R7 and also updated the CMS to 4.0.7

Can someone please help me? This is what i get from the log:

4274666 5c878c2 21-02-2024 08:46 XMDS POST ERROR Display RequiredFiles Unable to copy asset
4274667 1542b5f 21-02-2024 08:46 XMDS POST ERROR Display Schedule Error getting the schedule. Unable to copy asset
4274669 a6283f5 21-02-2024 08:46 PLAYER POST ERROR Display [2027] [CollectionInterval] [HTTP] 500 Internal Server Error
4274721 6c418cd 21-02-2024 08:46 PLAYER POST ERROR Display [2027] [CollectionInterval] [HTTP] 500 Internal Server Error
4274719 5874e5c 21-02-2024 08:47 XMDS POST ERROR Display RequiredFiles Unable to copy asset
4274720 2ff72ac 21-02-2024 08:47 XMDS POST ERROR Display Schedule Error getting the schedule. Unable to copy asset