Make sure that the controller has a parameterless public constructor.

StructureMap cannot wire up the dependencies in the REAL Controller constructors when you see this error. Maybe a NuGet package is jacked up.

 
 

Addendum 3/27/2017: At a closer look this has to do with an inability on the part of StructureMap to autowire up a dependency for an MVC5 Controller constructor. This ended up being a circular reference problem in which one repository, hydrated at a constructor by IoC, hydrated another which attempted to hydrate it. One of the two repositories was a dependency IoC hydrated at the constructor for the controller.