System clock synchronization is the most common issue
The codes generated by your authenticator app depend on your device having the correct date and time. If your codes are not working, you may have to sync your device's clock to get the correct date and time.
There are different ways to synchronize the device clock, which may vary by brand and model.
1. Launch the iPhone Settings app and selectGeneral.
2. Select Date & Time.
3. Make sure that Set Automatically is turned on.
If the option was enabled already, try turning it off and back on to force it to synchronize.
If you are using the Google Authenticator app:
- Open the Google Authenticator app
- Tap on the ellipsis menu and select Settings
- Tap on Time correction for codes
- Tap on Sync now.
If you are not using the Google Authenticator app, go to your device date settings and make sure that you are using a network-provided time. Normally, toggling on/off this setting will update the device date-time, if it doesn't, you can also try restarting your device.