Try these things first:
Check to make sure you are logging in from the place that you signed up with: email, Facebook, Google, or Apple.
Reset your password.
For an immediate fix, try to:
Update via App Store: Check your app store and update to the latest release.
Uninstall and reinstall the app.
If you need further assistance, please submit a Bug or Issue Report and it will be reported to our team ASAP.