We have a huge problem here. It is an API server based on C# .NET 4.6. The problem: All requests that hit the IIS of the backend server are not or only very slowly processed (see screenshot). In most cases, the requests are in the BeginRequest state and thus at the very beginning of the request lifecycle of the IIS pipeline. Most of them get stuck there and are kicked out again after a 30 second timeout. What can I say:

• The implementation is largely asynchronous
• There are no DB locks
• The CPU load is around 10-15%, so it doesn't seem to be a problem.
• The requests usually come from outside, but can also come from the same server, but that makes no difference
• No changes have been made to the environment or code.
• The last Windows updates are all on it and have been for a while (so everything was still running).
• We are running on Windows Server 2016 with IIS 10.

I will take any advice. Also ideas for further debugging on IIS with further information.

Update:

Hello everyone, a quick update and new findings. Regarding your answers, the application was running fine until recently. We did a log or performance analysis but with no results as the requests don't even make it to the code. Also the IIS logs on the base level did not show anything.

But now we have an approach. We are using Kaspersky and it seems to be getting in the way. We are already looking, but maybe one of you knows such a problem and has an idea.

Updates with new findings to follow. Thanks for the support

IIS Requests