Windows Server 2008R2 IIS Appcrash

Solution 1:

You can see that it mentions System.StackOverflowException, which is quite rare to occur, so that is a good starting point for investigation. The second information you have is that it started recently.

If you do have a version tracking system, try to locate all application updates within the relevant time range and look for any kind of recursion (direct, indirect, ...). StackOverflow is usually caused by recursion in your code that went out of control.

If the code is not obvious (i.e. it is not easy to find any such recursion, or there are too many recursions in the code and you can not identify the one that is causing the problem) you should try to put logs there. Place log entries into various places of your code so that you can recognize when certain functions were entered and leaved in the execution flow.

Since you have a crash every 15 minutes, you should be able to debug this using logs very quickly, because you will clearly see the problem in the logs once you put logs in the right (buggy) function.