iPad Air & iPhone 5 w IOS8 suddenly won't text (iMessage BAD) send is gray or Red?
You said you had to change your Apple ID email associated with your account. I just want to make sure you signed out of the old one and signed in with the new email address under "Settings > Messages > Send &amp; Receive" on both devices. After you do this, uncheck Settings > Messages > iMessage, wait 15 minutes and check it again.