To resolve the issue of your Volvo not always remotely locking or starting, and displaying a "vehicle in use" message, follow these steps:

1. Check Vehicle Status: Ensure your vehicle is parked, turned off, and locked. The remote functions may be restricted if the vehicle is not properly secured or is in motion.

2. Update the App: Make sure the Volvo On Call (VOC) app on your smartphone is updated to the latest version. An outdated app may cause connectivity issues. You can check for updates in the App Store.

3. Restart the App: If the issue persists, force close the VOC app and restart it. On iPhones, you can do this by swiping up from the bottom of the screen and then swiping up on the app to close it.

4. Reinstall the App: If restarting doesn't solve the problem, uninstall the VOC app from your device and then reinstall it. This can often resolve issues with app functionality - learn more - learn more.

5. Verify Connectivity: Check your phone's internet connection, as the VOC app requires a stable connection to communicate with your vehicle.

6. Check Battery Issues: Inspect your vehicle's battery status. If the battery is low, it may limit the remote features. Consider performing a battery health check.

7. Consult the Dealer: If the problem continues, visit your Volvo dealer. They can run diagnostics on your vehicle and account for any underlying issues that may not be evident, such as software glitches or battery malfunctions.

8. Reach Out for Support: If unresolved, contact Volvo customer service. They can provide guidance specific to your vehicle's model and app version and ascertain whether there are any known issues affecting remote functions.

By following these troubleshooting steps, you should be able to address the remote locking and starting issues with your Volvo vehicle.