I have an ASP.NET WebAPI project where I am attempting to replace our old XmlDocumentationProvider page with Swagger UI. I am using the swashbuckle swagger for webAPI 5.3.1
I think this is a known bug when you use non standard serializer or configuration of your web api is non standard.
It is a a circular reference problem.
see the issue in git hub repository : https://github.com/domaindrivendev/Swashbuckle/issues/486