Your connection or your device may be causing this problem. So check that you’re connected to the internet first, then check whether you maybe need to update the app. Tap ‘Update’ or ‘Updates’ in the App Store or Play Store. If you just see ‘Open’, you have the latest version already installed. In that case, you may need to install a software update for your phone.
Technical errors sometimes occur in the app. When this happens, you’ll see a message on the log-in screen. Please try again later in that case.