If this is for a disconnected WSUS server, you need to follow
and it requires 2 WSUS servers - 1 Online and 1 in the Disconnected state.
Also, review my guide
Part 4 deals with the policies and part 5 is the GPOs. I'm not sure if your private is using GPOs because you mention it's a standalone WSUS - so is that workgroup or domain joined? If workgroup, then you will configure 1 client through local group policy, and then export/import the registry settings for
'HKLM:\Software\Policies\Microsoft\Windows\WindowsUpdate'
and import them on each individual machine. If your machines are still showing up incorrectlyIs it possible to update the BIOS on any of them to test if that's the issue?
https://www.ajtek.ca/wsus/are-your-computers-to-blame-for-the-wsus-mmc-console-crashing/
If they are all connecting but only 1 is showing up, you may have an issue with a duplicate WsusClientId which can be solved by the client side script:
https://www.ajtek.ca/wsus/client-machines-not-reporting-to-wsus-properly/