Hi. I have recently received a new sim for my son who has an iPhone 5s that was previously my daughters. I have activated the sim and can make calls and messages etc but it will not allow me to activate the iMessage feature. Please help!!
You may need to activate iMessage with the new number, Try this
I have tried all these options and it still isn’t working. It just keeps saying activation unsuccessful
You may need to factory reset the iPhone to remove any other accounts on the phone, then register the phone with your sons iTunes account.
You may then need to sync with iTunes to get the carrier settings.