To resolve the issue of the Hero Band III App displaying a message that it has stopped and needs to close, follow these step-by-step instructions:

1. Restart Your Device
- A simple restart can sometimes resolve temporary glitches. Power off your Android device, wait for a few seconds, and then turn it back on.

2. Clear App Cache and Data
- Go to Settings on your device.
- Tap on Apps or Apps & notifications.
- Find and select the Hero Band III app from the list.
- Tap on Storage.
- First, tap on Clear Cache. Then, tap on Clear Data. Confirm any prompts. This will remove temporary files and reset the app settings, which may resolve the crashing issue - learn more.

3. Check for Updates
- Ensure that your Hero Band III app is updated to the latest version.
- Open the Google Play Store.
- Search for Hero Band III.
- If an update is available, tap Update.

4. Reinstall the App
- If the problem persists, consider uninstalling and then reinstalling the app.
- Long press on the Hero Band III app icon, select Uninstall, and confirm.
- Open the Google Play Store, search for Hero Band III, and tap Install to reinstall the app.

5. Check Device Storage
- Insufficient storage can lead to crashing apps.
- Go to Settings > Storage to verify if there’s adequate space. If not, consider deleting unnecessary files or apps.

6. Check for System Updates
- Ensure your Android OS is up-to-date, as system updates can often resolve compatibility issues.
- Go to Settings > System > System updates and check if there are any pending updates.

7. Reset App Preferences
- This will reset the app settings without losing any data.
- Go to Settings > Apps > Tap the three dots in the top right corner and select Reset app preferences.

8. Contact Support
- If none of the above steps work, consider reaching out to the Hero Band III support team. Look for contact information within the app or on the app's official website.

These steps should help you resolve the issue with the Hero Band III app crashing on your device.