New iphone SE wont connect with carplay although other phones do connect

Hello and welcome to Apple Support Communities, paulthediver!

We understand you're not able to connect with CarPlay on your iPhone SE and you've verified that other iPhone devices do connect. We'd be happy to help you troubleshoot this.

The steps here may help you out: If you need help with CarPlay

Especially Step 7, as this can make a difference:

7. Make sure that your CarPlay stereo is using the latest firmware from the car manufacturer. Check your car's manual for more information.

Have a great day!