Debugging an IIS application crash

I have an ASP.NET application that crashes all the time. It seems like a memory heap or stackoverflow exception and there is thus nothing logged.

I have used the DebugDiag tool to write a crash dump file when the crash occurs and I indeed get the crash dumps. However, finding the error from those crash dumps is not as easy as I thought.

I open the crashdump file in Visual Studio 2015 and choose the option "debug with managed only". Then I get the message "No compatible code running, the selected debug engine does not support any code executing on the current thread". Ok, so it seems then that the error occurs in unmanaged code. And so I choose to debug in mixed mode, but then I get the message that the source is not available.

What I tried next was to run the DebugDiag analyzers themselves on the crash dump file. The result was the rather crytic message: In w3wp__Exception 0X80000003.dmp the assembly instruction at verifier!VerifierStopMessage+273 in C:\Windows\System32\verifier.dll from Microsoft Corporation has caused a breakpoint exception (0x80000003) on thread 5. Please follow up with the vendor Microsoft Corporation for C:\Windows\System32\verifier.dll

So how can I proceed from here to find the cause of the crash?