After upgrade I can no longer log in

I love the design and functionality of the new app. But I can no longer log in after upgrading to 3.0 and 3.1, neither with my Swiss user credentials, nor with my Miles and More account. Obviously the same credentials work fine when logging on via the website or even the mobile website. As much as I enjoy the new design, I can no longer use the app this way, after being dependent for the last 5 years. Very disappointed...

Smailz about SWISS, v3.1.1