To resolve the issue with the clock not functioning on your FlagFit 2.0, follow these detailed steps:

1. Restart the Device:
- Turn off your FlagFit 2.0 by long-pressing the screen touch spot for around 5 seconds. Wait for a few moments and then turn it back on.

2. Check Bluetooth Connection:
- Ensure that your smart bracelet is properly connected to your smartphone via Bluetooth. Open the Bluetooth settings on your phone and check if the FlagFit device is listed as connected. If it is not connected, try reconnecting it.

3. Sync Date and Time:
- Open the FlagFit 2.0 application on your smartphone. Navigate to the settings or synchronization options and ensure that the date and time are being synced properly from your phone to the device. This can often help reset any incorrect clock settings.

4. Update the App:
- Make sure you have the latest version of the FlagFit 2.0 app installed on your smartphone. Visit the Google Play Store, search for FlagFit 2.0, and update it if a new version is available.

5. Clear App Data:
- If you are still experiencing issues, consider clearing the app data. Go to your phone’s settings, find the FlagFit 2.0 app in the application manager, and select ‘Clear Data’. Note that this might require you to log in again and re-sync your device.

6. Reinstall the App:
- Uninstall the FlagFit 2.0 app from your phone and then reinstall it from the Google Play Store. This can help fix any underlying software issues that might be affecting your device.

7. Factory Reset the Device:
- If the clock still does not work, consider performing a factory reset on the device. This typically involves pressing and holding the menu button/join button until you see a reset option. Be aware that this will erase all data on the device.

8. Consult Device Manual:
- Reference the user manual for specific guidelines related to your FlagFit 2.0 model. The manual includes troubleshooting steps that may be specific to your device learn more.

9. Seek Professional Help:
- If all else fails, it might be time to contact the manufacturer’s support team or visit a service center for further assistance.

By following these steps, you should be able to resolve the issue with your FlagFit 2.0 clock. If the problem persists after trying these suggestions, further technical support may be required.