On a customer’s site it was using an InfoPath form which connects to the GetUserByProfileName web service when we were opening the URL we were been faced with event ID : 5566. The InfoPath form is administrator approved via central admin. We were using a AAM address which produced the error. I checked a couple of things and ensure the web application wasn’t using anonymous authentication. I checked the bindings in IIS and the AAM wasn’t present after adding the binding the error was resolved.