On Monday, July 8, Microsoft will decommission one of its synchronization servers. Failover to the new architecture is available, but organizations that are still connecting to the old endpoint may experience a slowdown in the initial sync.
According to Microsoft…
On Monday, July 8th, the WSUS synchronization endpoint fe2.update.microsoft.com will be fully decommissioned and no longer reachable. For WSUS servers that are still configured for the old endpoint, this change should result in a one-time slow sync (typically just a few minutes) as the WSUS server automatically switches to the new endpoint. Although the switch should occur automatically, if you encounter synchronization errors after Monday, see the KB article below for steps to verify if you are affected by the problem and the steps to fix it:
4482416 – WSUS synchronization fails with SoapException (https://support.microsoft.com/en-us/help/4482416/wsus-synchronization-fails-with-soapexception)