Double check that the iCloud account email is the same one that is used for Messages activation. Here is how:
- Open Settings ➔ Tap on Apple ID (Your Name at Top) ➔ Look at the bottom of your Apple ID. There should be an email address. Make note of it.
- Open Settings ➔ Messages ➔ Send & Receive : All the way down should be Apple ID and an email address. This email address must be the same as the one noted in Point 1.
Axel F.