Dolphin does not recognize Classic controller for wad file

[velt]

So I want to play mario tennis 64 in the VC on dolphin.
I go to configuration, controllers and set the extension of the emulated wiimote to classic controller (i use an xbox controller).
But everytime I launch the game it says "you will need the classic controller".

Any ideas why it is not working?

[JosJuice]

Do the buttons work once you're in the game? The "You will need the Classic Controller" always shows up, even if you have a Classic Controller configured correctly.