WSUS Synchronization in ConfigMgr 2012R2 fails with HTTP 503 / WSUS Pool Stopped

Today I realized that I had machines that were not getting their updates from our WSUS server after a couple of people complained that websites were telling them Silverlight was out of date. I also noticed that newly loaded machines were getting their assigned software but were not installing any windows updates.

I first looked at the IIS log files for the WSUS server and noticed a bunch of 503 responses to machines checking in for updates. I next checked the SCCM Site Server and looked at the site status and noticed an issue with the SMS_WSUS_SYNC_MANAGER component on the primary site server. It showed errors that looked like this.

Message ID: 6703
WSUS Synchronization failed.
Message: The request failed with HTTP status 503: Service Unavailable.
Source: Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer.

When I tried to access the WSUS URL for the WSUS Administration website (i.e., http://wcboe-sccm.wcs.local:8530) it failed with the error:

HTTP Error 503. The service is unavailable

The problem turned out to be that the WsusPool Application Pool in IIS is in a stopped state, as we can see below.


The solution turned out to be that the Wsus IIS Pool was running out of memory and entering the stopped state. The Private Memory Limit (KB) for the Application Pool default value of 1843200 KB was insufficient. I read that you should increase this limit to 4000000 KB. You access this by loading IIS Manager, clicking on Application Pools in the left windows, click on WsusPool in the middle window to highlight it, then clicking on Advanced Settings in the right window under Edit Application Pool.

After the Application Pool has been restarted, monitor the SMS_WSUS_SYNC_MANAGER component status, wcm.log and wsyncmgr.log for failures. You can also set this setting to 0 (zero) which will allow the WsusPool to use as much memory as it needs.

WSUS Logs with error info.

You can see this issue in the WCM.log from the primary site server. It will contain numerous entries similar to the following:

The request failed with HTTP status 503: Service Unavailable or Remote configuration failed on WSUS Server.

The wsyncmgr.log from the primary site server will show errors similar to the ones below:

Sync failed: The request failed with HTTP status 503: Service Unavailable or The request failed with HTTP status 503: Service Unavailable.

About The Author

I have worked in the computer repair field since the early '90s. I was a technician and then Coordinator of Computer Repair for Regional Education Service Agency II (RESA 2) for 18 years. I currently work for Wayne County Schools as a Network Engineer/Technology Specialist. I am responsible for the schools' Internet access, Wi-Fi, networks, servers, laptops, desktops, and operating systems and software.

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