Hello,
If WSUS server crashed, client will not contact. Or WSUS server not crashed, client still not contact.
Meanwhile I suggest that check the WSUS server system event log firstly, check event id just like 1001,41, 6008, any detaied error message has been recorded.
Review WSUS Logs, examine the WSUS logs located in the %windir%\WindowsUpdate.log and %ProgramFiles%\Update Services\LogFiles folders for any error messages or clues about the issue.
Best Regards,
Hania Lian
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