Weird, annoying problem: I can receive text messages but not send them. I get "error sending message." I'm on AT&T running a non-jailbroken iPhone 3G with firmware 2.2. I've been on a phone a couple of times with AT&T. They've removed/replaced the text plan. I've reset my network settings, restored my phone from backup, restored my phone from a newly-downloaded firmware, but to no avail. My SMS message center number is set to +13123149810. Any help would be greatly appreciated. For clarity, I got a "new" iPhone within the last couple of weeks due to a problem with my old one. I also had an employee discount applied to my account in that timeframe. I'm convinced that the problem is on ATT's end. I just wish I could remember exactly when I first had trouble with the texting but it was recently. I just can't pin it down to which event (probably) caused it. Help!