Problem with simply MultiView

Guys I have a little problem that I can not solve since half an hour, probably because I'm getting angry. Basically I have two simple views that I'm using to test some things: I'm supposed to press the button of the first view to switch to the second one, but it keeps giving me an error, here's the code:

The error I get on click is: "Could not cast value of type 'MultiView.ViewController2Class' (0x104d7fed8) to 'MultiView.SecondViewController' (0x104d7fd08)."