No AuthenticationProvider found for UsernamePasswordAuthenticationToken

As you already wrote in your comment the problem is that you always return false in the supports() method of your autentication provider. But instead of always returning true you should check the authentication you get like this:

public class MyAuthenticationProvider implements AuthenticationProvider, Serializable {

    @Override
    public boolean supports(Class<? extends Object> authentication) {
        return (UsernamePasswordAuthenticationToken.class.isAssignableFrom(authentication));
    }

    // ...
}

I had the same issue. In my case the solution was to set AbstractAuthenticationToken.setAuthenticated to true after the authentication passed.