My 3G iPhone has stopped sending text messages to one specific number. It says its sent but it does not arrive. Any ideas?
Are you seeing this problem when sending a SMS, MMS or iMessage? Does it go away if you disable MMS or iMessage in Settings > Messages?
Make sure the phone number that you aren't able to send texts to has an area code.
If that doesn't help, take a look at this Apple doc -> iOS: Troubleshooting Messages
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