Thanks for the detailed information!
HangFire uses JobActivator class to create instances of your classes, in your example it is the FileImportController. Default JobActivator implementation can construct only classes with default constructors, and this is the default behavior for ASP.NET MVC’s dependency resolver either.
To be able to use non-default constructor, you should empower HF with the IoC container:
If you are using another IoC container, don’t worry, just implement its support by example, and use it in your code JobActivator.Current = new YourImplementation().
P.S. You can fix this, re-build the application and try the Retry button on a previously failed job.