For any issues on the iOS app please try to reinstall the app from your mobile device:
- Remove the app from your device.
- Power cycle your device (Turn your device off and then on again)
- Reinstall the app on your device.
If you continue to have trouble, install any available updates for your iOS. If these suggestions do not resolve the issues you are encountering, please try accessing the app through a different network or Wi-Fi connection to see if the same issues occur.
For more detailed information please visit the official iPhone support page or the official iPad support page.