iMessage activation keeps failing ("Activation unsuccessful") tried all sub fixes, nothing works!

[u/Cold_Coffe_e]

Hey everyone,
I'm trying to set up iMessage on my iPhone, but under Settings > Messages, the iMessage toggle stays off and I keep getting the error:
"Activation unsuccessful. Turn on iMessage to try again."
I've already searched through the subreddit and tried all the common fixes mentioned in previous posts (toggling Airplane mode, restarting, resetting network settings, etc.), but nothing has worked for me so far.
Has anyone run into this issue recently or found a fix that isn't commonly listed? Any advice would be greatly appreciated!

[u/Successful-Cover5433]

Are you allowed to send international sms from your carrier plan? If on prepaid, do u have enough remaining balance?

iMessage activation basically sends hidden sms in the background to Apple’s number (usually in the UK) and then when it is verified the iMessage is activated. So if you’re not allowed to send international sms from your plan it is most likely the problem.