Two Different IIS Servers Stopping Applications

Question

Hello,

We have two different IIS servers running two completely different sites. Both are encountering the same issue. The application pool stops and then site shows a 503 error.

In event viewer, I see a lot of logs like this on both servers.

A process serving application pool 'CONTOSOAPP' suffered a fatal communication error with the Windows Process Activation Service. The process id was '4900'. The data field contains the error number.

I've ensured that .NET CLR Version is set to v4.0 and Enabled 32-bit Applications is True.

This began on both machines around the same time. I suspected Windows Update and have recovered the machines to their state prior to the updates. However, the issue remains.

Answer 1

Hi @Anonymous ,

IIS comes with a feature called Rapid-Fail Protection. By default an App Pool is configured to become disabled if a worker in the pool crashes 5 times within a 5 minute span. The thresholds of this setting are able to be modified by right clicking on the App Pool going to Advanced Settings and modifying the 'Rapid-Fail Protection' properties.

Microsoft Learn records that event ID 5002 can be resolved by debug the application and restart application pool. You must have membership in Administrators.

• Correct any problems in the application that was running in the worker process. The application may have to be debugged and retested.
• Restart the application pool.
  1. Click Start, click Control Panel, and then click Administrative Tools.
  2. Right-click Internet Information Services (IIS) Manager and select Run as administrator.
  3. In the Connections pane, expand the computer node for the Web server and select the Application Pools folder underneath it.
  4. In Features View, select the application pool you want to restart.
  5. Right-click the application pool and select Start.

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Best regards,
Bruce Zhang

Answer 2

The issue was due to Cylance 2.1.1584

Found here
https://learn.microsoft.com/en-us/answers/questions/590694/net-runtime-errors-iis.html