iMessage activation unsuccessful

Hello asesh0304,

Thanks for using Apple Support Communities. It looks like you recently reviewed the best article for this issue, If you can’t turn on or sign in to iMessage or FaceTime on your iPhone - Apple Support. The error message you mentioned is addressed there. Did you have a chance to try those steps? As the article recommends, if you have tried all sections and this continues, wait 24 hours and try again.

"If your phone number still doesn’t have a check next to it in Settings after 24 hours

It might take up to 24 hours for your carrier to verify your phone number with Apple. Contact your carrier to make sure that you can send and receive SMS messages and wait up to 24 hours after you try the troubleshooting steps above."

For further assistance, reach out to Apple Support from Get Support.

Kind regards.