An error occurred during iMessage activation
my iMessage hasn’t been working all day today and I really need it to work! Please help me fix it
[Re-Titled by Moderator]
Try first to optimize the range of the mobile network, see this Apple article:
If you see No Service or Searching on your iPhone or iPad
If you see No Service or Searching on your iPhone or iPad - Apple Support
Check the Wi-Fi connection , see the following Apple articles:
Connect to Wi-Fi on your iPhone, iPad, or iPod touch
Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network
If your iPhone, iPad, or iPod touch won't connect to a Wi-Fi network - Apple Support
See also this Apple article: If you can’t turn on or sign in to iMessage or FaceTime
If you can’t turn on or sign in to iMessage or FaceTime - Apple Support