WSUS Synchronization Issues Begin July 9, 2025: Causes and Troubleshooting Tips

Here’s a summary of the issues described in the BornCity blog post "WSUS has synchronization problems (July 9, 2025)":

What Happened?​

• Since July 9, 2025, administrators have reported that WSUS (Windows Server Update Services) is unable to synchronize with Microsoft’s update servers.
• Attempts to download the July 2025 security updates fail; the Microsoft update endpoint is unreachable.
• Errors in SoftwareDistribution.log include messages like:
• "The connection to the remote server cannot be established."
• "A connection attempt failed because the remote station did not respond" (with various Microsoft server IPs).

Reports From Different Organizations​

• Several IT administrators in Germany and Czech Republic confirmed that their WSUS servers failed to sync, starting between 2:00 a.m. and 7:00 a.m. C.E.T. on July 9, 2025.
• Sync failures were observed across different environments, including Server 2025 and Server 2016.
• Some report that synchronization was working late on July 8, but failed after midnight or in the early morning hours of July 9.

Error Samples​

• System.Net.WebException: The connection to the remote server cannot be established.
• System.Net.Sockets.SocketException: A connection attempt failed because the remote station did not respond correctly after a certain period.
• Timeouts and disconnections are commonly mentioned.

Symptom Consistency​

• The issue is affecting WSUSs whether they use or don’t use a proxy.
• A manual sync attempt simply hangs at 0%, and different error text may depend on the server’s role, connectivity, and network route.

Possible Connections to Updates​

• The post mentions Microsoft update KB5062557 for Windows Server 2019, which includes changes to the Microsoft RPC Netlogon protocol, but it's unclear if this is directly related to the WSUS issue.

Additional Notes​

• Affected endpoints like sws.update.microsoft.com were reportedly not found during troubleshooting.
• No cause or official explanation from Microsoft is given at publication time.

In summary:
There is a widespread, international WSUS synchronization outage, starting July 9, 2025, with no clear resolution or workaround yet. The log errors point to remote server unavailability, and manual sync attempts also fail.
For official updates or troubleshooting advice, administrators should monitor the original BornCity article or Microsoft's update status channels.

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Source: BornCity WSUS has synchronization problems (July 9, 2025) | Born's Tech and Windows World