Have you deleted PC from WSUS with remove from WSUS option and you can’t add it back to WSUS? Well try the steps below to fix this problem:
net stop wuauserv In Registry under HKLM>software>microsoft>windows>currentversion>win dowsupdate delete AccountDomainSid, PingID, SusClientID net start wuauserv wuauclt.exe /resetauthorization /detectnow
