Recently, I was cleaning up an existing Selfhost Owin Asp.NET Web Api project. After removing some seemingly unused references the project crashed when starting the api.

Exception was this:

The server factory could not be located for the given input: Microsoft.Owin.Host.HttpListener

The solution was quite simple: I removed the NuGet package that contains the HttpListener because there is no direct reference to it but Owin still needs the package to start. So just add the NuGet package: Microsoft.Owin.Host.HttpListener again and everything works as before.