iMessage activation error

[A2L]

My iMessage stopped using phone number to send and receive. Just started happening has been working fine all this time. No new updates on phone. Keep getting activation error 

[umnikke8]

Try turning off iMessage, logging out of Apple Account. Things like that should reset it and get it to reconnect.

[hairbag1]

@A2L 

in you iPhone settings, make sure your number is correct and iMessage is toggled ON.

[softech]

@A2L you just activated with PM and ported in the number?

make sure you removed all the old sim card , or if old one is an eSIM, disable it.  Make sure only PM sim is enabled, and set with label Primary.  Then Reset network settings after a device reboot.  Check to see if it works

if not, you will need to reactivate iMessage.  Go to Settings >Phone > My Number and manually remove it.  Reboot phone and then go back Settings >Phone > My Number  and manually add the number back to re-register iMessage