You can follow these steps to troubleshoot and enable sound notifications:

1. Check Odoo Mobile App Notification Settings: 

   Go to the notification settings within the Odoo mobile app (usually found under your profile or general settings). Ensure that the "Sound" option for notifications is turned on, if available.

2. Verify Phone Notification Settings: 

   Make sure notifications are enabled for the Odoo mobile app on your phone, and confirm that the "Sound" setting is enabled for the app's notifications.

3. Battery Optimization Settings: 

   Some phones restrict background activities to save battery, which may prevent the Odoo app from delivering timely notifications with sound. Make sure the Odoo app is excluded from battery optimization settings.

4. Update the App: 

   Updating the app may resolve notification issues.

5. Reinstall the Odoo App: 

   Uninstalling and reinstalling the app can reset notification settings and resolve sound issues.

Once these steps are applied, you should be able to receive sound notifications from the Odoo mobile app. Let me know if it helps!