WSUS Problem After Upgrading SCCM serve from 2012 R2 to 2019

Question

Hello Everyone

hope all is well

I have followed the steps for SCCM server IPU and all went well, however, I'm having a bit of strange issue with WSUS.

It looks like WSUS is syncing and pulling updates successfully:

However, I'm getting these errors in components status :

and as you can see below, it is showing that WSUS sync has been failing constantly :

Error:

SMS_WSUS_SYNC_MANAGER 6703 WSUS Synchronization failed. Message: Failed to sync some of the updates. Source: Microsoft.SystemsManagementServer.SoftwareUpdatesManagement.WsusSyncAction.WSyncAction.SyncUpdates.

I tired reinstalling the WSUS and SUP by removing the role from the server and SCCM but no luck. When I tried wsusutil rest, the WSUS snap in froze and gave this error :

Any idea on what the issue might be ?