First, try the steps below:
Restart your mobile phone
Please ensure your phone Internet connection is stable
Please use the application without multi-tasking (restart your mobile and run the app while no other app is running at the same time).
If these don't solve the problem:
Reinstall the app and log in again
How to log in:
In the [Sign up / Login] dialog, select to login with Facebook or login with your email address.
If this doesn't solve your problem, please contact us.