Try these troubleshooting steps in order:
- Close and reopen the app: Swipe up from the bottom (iOS) or use the recent apps button (Android) and swipe the app away, then reopen it.
- Restart your device: Power off and on your phone or tablet.
- Check for updates: Make sure you're running the latest version of the app.
- Clear app cache (Android): Settings → Apps → [App Name] → Storage → Clear Cache
- Reinstall the app: Delete the app and download it again from the app store.
If the problem persists, please submit a support request with details about the issue.