I'd be happy to help you out with your question. Sorry for the inconvenience caused.
To resolve this issue please try following steps :-
First, check the event logs on both the upstream and downstream servers for any errors or warnings related to WSUS or Windows Update. This will help you identify the root cause of the issue.
Next, restart the WSUS service on both the upstream and downstream servers to see if that resolves the problem.
If that doesn't work, try resetting the downstream server's update status by running the following command on the downstream server: "wuauclt /resetauthorization /detectnow". This should force the downstream server to re-register with the upstream server and report its update status.
Also, check the firewall settings on both the upstream and downstream servers to make sure that the necessary ports are open for WSUS communication.
Make sure that the downstream server is pointing to the correct upstream server in its WSUS configuration.
Finally, if none of the above solutions work, you may need to remove the downstream server from WSUS and re-add it as a new downstream server. This will require re-approving updates and may take some time to complete, but it should reset the server's status and hopefully resolve the issue.
If you have any other questions or need assistance with anything, please don't hesitate to let me know. I'm here to help.
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