WSUS Clients Can See Updates But Not Download Them – Microsoft Q&A

The Windows Update KB KB5019966 for Windows Server 2019 was installed on my WSUS server and since then it rebooted and then sat at the black screen during boot up and spun. So we turned it off and tried Automatic repair, safe mode, safe mode with networking, last known good configuration and it would not boot.

https://learn.microsoft.com/answers/questions/1100408/wsus-clients-can-see-updates-but-not-download-them.html