Try these fixes first to check if you can get your app working again:
- Sync your authenticator app time. For example, authenticator app has this feature under Settings > Time correction for codes > Sync now.
- Automate your mobile phone time. If your authenticator app doesn't support time syncing, you can automate it in your device's general settings:
a) Android: Settings > General Management > Date and time > Automatic date and time
b) iOS: Settings > General > Date & Time > Set Automatically - Sync your mobile phone and desktop times.
- Clear your mobile cache or desktop browser cache and cookies.
- Try entering codes on different platforms: Coinstore website in desktop browser, Coinstore website in mobile browser, or Coinstore mobile app.
If this doesn't help, you'll need to change or unlink your authenticator app. For your security, you won't be able to withdraw funds within 24 hours after changing or unlinking your authenticator app.