Can't get login to work in Cakephp 3.3

I try to make a custom plugin, but when I try to implement login I can’t get it to work - I have tried to follow several guides and using the API documentation, but still when entering the current username and password, it says it’s wrong…

Problem solved - The problem was that I had tried to map username and password to different db-fields, so when I drop that I get it working…