Cannot activate iMessage or FaceTime

You might want to make sure you have set up FaceTime and Messages the way Apple suggests:

Set up FaceTime on iPhone – Apple Support

Set up Messages on iPhone – Apple Support

Re: "Cannot activate iMessage or FaceTime"

Trouble shooting:

If you can’t turn on or sign in to iMessage or FaceTime - Apple Support

says:

Still not activated after a day? 

It might take up to 24 hours to activate iMessage and FaceTime. If the issue continues after 24 hours, follow these steps:

1. 1. Make sure that your device has the latest version of iOS or iPadOS.
   2. If you're using an iPhone, contact your carrier to make sure that you can send and receive SMS messages.
   3. Make sure you can send and receive SMS. If a prompt appears stating "Your carrier may charge for SMS messages used to activate FaceTime and iMessage", tap "OK" to allow possible SMS charges.
   4. Contact Apple Support.

All the best :-)