imessage activation
an error occurred during activation try agian ... please help me
iPhone 7
Messages - If you get an error when trying to activate iMessage or FaceTime
Messages Troubleshooting
Do you have access to another WiFi network where you can try? That has worked for several people.
Try a restart.
Restart your iPhone, iPad, or iPod touch
Try a forced restart.
If necessary
Hard reset
Do a backup and try a factory reset. Then restore from your backup.
Backup - Restore your device from an iCloud or iTunes backup