Sometimes you find your WSUS server keeps crashing over and over again. WSUS is unavailable and/or the WSUS management console hangs. When you start to investigate as to why Windows Server Update Services crashes, you’ll notice the following error message being logged in the HTTPErr log files:
2017-05-08 05:03:53 203.0.113.144 56433 203.0.113.4 80 HTTP/1.1 POST /SimpleAuthWebService/SimpleAuth.asmx 503 707060612 AppOffline WsusPool
In the Eventlog you might find an error like:
The WSUS administration console was unable to connect to the WSUS Server via the remote API.
Verify that the Update Services service, IIS and SQL are running on the server. If the problem persists, try restarting IIS, SQL, and the Update Services Service.
And sometimes clients checking for Windows Updates would quickly error out with a code
0x80244021 which indicates the inability to reach WSUS.
How to improve Windows Server Update Services (WSUS) availability
To improve WSUS availability, you need to increase IIS Private Memory Limit. The default limit is set to 1843200KB. And when an IIS worker process uses more than 2GB WSUS crashes and the problem occurs.
Change Private Memory Limit (KB) to a higher number that fits your server specifications or simply
0 , which means no limit, instead of the hard-coded 1843200. Follow this path to find the setting:
Internet Information Services (IIS) Manager → Server → Application Pools → Select “WSUSPool” → Actions Advanced → Recycling → change “Private Memory Limit (KB)“.
This’ll improve WSUS availability.