iMessage activation unsuccessful
My iMessage isn’t working and I don’t know why
Did you turn on the iMessages slider so it shows green?
See the Apple Support article(s) below.
If you can’t turn on or sign in to iMessage or FaceTime. *
If you can't send or receive messages on your iPhone, iPad, or iPod touch *
Some things you can try. Do you have access to another WiFi network where you can try? That has worked for several people.
Try a restart.
Try a forced restart. See the section towards the end of the article.
Reset Device. -
If necessary
Hard reset. -
Do a backup and try a factory reset. Then restore from the backup.
Restore - If you see an error when you update or restore your iPhone, iPad, or iPod. *
Backup - Restore your device from an iCloud or iTunes backup. *