Fixing WSUS sync error "WebException: The remote server returned an error: (403) Forbidden."

Here's an issue we see every once in a while in product support and since I didn't see it documented very thoroughly anywhere else I thought I would do a quick write up in case you happen to see this some day on your WSUS box.

Issue:  When the WSUS attempts to sync with the Microsoft update site, either automatically or manually, you may see the following error:

An HTTP error Occurred

WebException: The remote server returned an error: (403) Forbidden.
at System.Net.HttpWebRequest.GetRequestStream()
at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
at Microsoft.UpdateServices.ServerSyncWebServices.ServerSync.ServerSyncProxy.GetAuthConfig()
at Microsoft.UpdateServices.ServerSync.ServerSyncLib.InternetGetServerAuthConfig(ServerSyncProxy proxy, WebServiceCommunicationHelper webServiceHelper)
at Microsoft.UpdateServices.ServerSync.ServerSyncLib.Authenticate(AuthorizationManager authorizationManager, Boolean checkExpiration, ServerSyncProxy proxy, Cookie cookie, WebServiceCommunicationHelper webServiceHelper)
at Microsoft.UpdateServices.ServerSync.CatalogSyncAgentCore.SyncConfigUpdatesFromUSS()
at Microsoft.UpdateServices.ServerSync.CatalogSyncAgentCore.ExecuteSyncProtocol(Boolean allowRedirect)

The dialog should look something like this:

In most of the cases I come across this is caused by an issue on the local network that is preventing proper access to one of the following sites:

• https://www.update.microsoft.com
• https://windowsupdate.microsoft.com
• https://download.windowsupdate.com
• https://download.microsoft.com
• https://wustat.windows.com

This could be because of a general Internet connectivity issue, an issue with your local proxy server or maybe the firewall itself.  A good way to check is to see if you can access all of these sites directly from the WSUS server itself outside of the WSUS console.  If you can't then this very well may be your issue.

This issue can be caused by other issues that are beyond the scope of this post but if this doesn't fix your issue then we have some good information on troubleshooting other WSUS sync issues here:

https://technet.microsoft.com/en-us/library/cc708514(WS.10).aspx

Hope this helps!

J.C. Hornbeck | System Center Knowledge Engineer