Always check the app store to ensure you have downloaded the latest version of the app. If you have an outdated version, you must first update this. Then try to log in again.
When you have the latest version and you still cannot log in, please contact our Support department during office hours (9am-5pm CET) via chat. You may also call us at +36 1 701 0047, or email us at firstname.lastname@example.org