Hi! I see you're having trouble locking, unlocking, and starting your 2025 Buick Enclave using the myBuick app on your iPhone running iOS 18.7. You mentioned you've already restarted the app, logged off, and logged back in, which are great first steps. Let's try a few more things to get this resolved.

1. Check Vehicle Connectivity:
Sometimes the vehicle's connection to the app might be interrupted. Make sure the Enclave is in an area with good cellular signal. Also, confirm that the vehicle's OnStar or connected services subscription is active since myBuick functions through these.

2. Verify App Permissions and Network:
On your iPhone, go to Settings > myBuick and ensure the app has permission to use Cellular Data. Also, check that your phone is connected to a stable Wi-Fi or cellular network.

3. Confirm Vehicle Visibility in the App:
In the app, see if your 2025 Enclave is properly listed and is showing its status (like fuel level, mileage, etc.). If your vehicle isn't showing or says it's offline, try refreshing the app.

4. Force Quit and Reinstall the App:
Since you restarted and logged out/in, the next step is a full reinstall. Remove the myBuick app from your iPhone and then reinstall it from the App Store. This can fix corrupted data or bugs.

5. Check for Software Updates:
Though you're on iOS 18.7, check if the myBuick app itself has any updates pending in the App Store. Also, check if your Enclave has any pending software or firmware updates—these often affect remote features.

6. Try Remote Commands After Waiting:
Sometimes remote commands like lock/unlock or start can be delayed if the system is updating or temporarily disconnected. Wait a few minutes after performing one command before trying another.

7. Additional Troubleshooting:
- Ensure no other Bluetooth devices are interfering.
- Check that the key fob battery is good, since some functions may rely on detecting proximity versus app commands.
- Verify your account's two-factor authentication status and that you've completed any prompted security steps.

If after these steps the app still won’t lock, unlock, or start your Enclave, there may be a server issue or something specific to your vehicle’s setup needing further investigation. Sometimes there are outages or glitches reported by other users as well1 2.

Would you like me to help check if there is a reported outage or provide you with direct contacts for myBuick app support? Also, can you share if you see any error messages in the app when you try to lock/unlock/start? That would help narrow things down!