HTTP Error 500.30 — ANCM In-Process Start Failure

This is one of the many issues that randomly occurs when you don’t expect it. Clearly something has changed but it’s rarely clear what. In my case this happened on a web service that had been running fine for a few weeks.

It was of those it works on my machine scenarios, which is a little frustrating as there were no patches scheduled on the server between now and when it was last published.

Fortunately the solution for me was simple I just added the following line to my main csproj file

<AspNetCoreHostingModel>InProcess</AspNetCoreHostingModel>

This works for me as the web service is .Net Core 3.1 (LTS) and I have the dotnet hosting bundle installed on my server.

I then published to the second instance of the same web service as it sits behind a farm, and the second instance got the same error as above despite the identical code on the first instance working fine!

After a little checking of the app pool settings I realised that for both app pools the Load User Profile setting had been incorrectly turned to False. There is no reason I would ever have done that. Setting the value to false means that it uses IIS 6.0 behaviour which is not what I want, particularly for a .net core app. I have no idea when or how this happened, particularly as one instance worked and the other didn’t. For both app pools I turned Load User Profile to True (the default value) and they both worked (for now!!).

If this doesn’t solve your issue there are some suggestions on StackOverflow as this error seems to cover a multitude of sins.

This issue occurred for me again and in this case the solution above didn’t work. In this case the issue was caused by a combination of issues.

1. The AppPool user permissions had disappeared from the site folder, so they needed to be restored.
2. An environment variable had reverted to an old value and had to be restored. This value was used in the apps startup and came to light in the application logs

At the moment I can only speculate what caused these but the server is a new one running Windows Server 2019.