Brand new iPad 10 purchased from Apple Store won't activate cellular. Says it's locked to another carrier.

Hello AppleBoy123,

Based on what you've told us, you may need to set up your iPad by connecting to a reliable Wi-Fi network instead. Once you have the iPad set up, you can then try to activate cellular service. For more information, check this out: If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

We think you'll find these steps helpful:

Follow these steps

1. Restart your iPhone or iPad.

2. If you're using a cellular-data connection, connect to a reliable Wi-Fi network instead.

3. If you get an error message on your iPhone or iPad that says the activation server is temporarily unavailable or cannot be reached when trying to activate, wait a few minutes, then repeat the previous steps.

If you still can't activate your iPhone or iPad, try again using your computer instead:

1. Make sure that you have the latest version of macOS or the latest version of iTunes.

2. Check that your computer has an internet connection.

3. With the cable that came with your iPhone or iPad, connect your iPhone or iPad to your computer. Locate your device on your computer.

4. Wait while your computer detects and activates your iPhone or iPad: 

* If an alert appears that says "Set up as New" or "Restore from Backup," it means your iPhone or iPad is activated.

* If you get an error message on your computer that says that the SIM card isn't compatible or is invalid, contact your carrier.

* If you get an error message that says the "activation information was invalid" or "activation information could not be obtained from the device," use recovery mode to restore your iPhone or iPad.

Thanks.