How can I fix my iPhone MMS send failed error on AT&T?
You are getting the notorious exclamation point when you try to send an MMS on your iPhone 3G or 3GS. There are a few steps you can try to fix the problem before you contact Apple or AT&T and they give you the same advice.
First check your AT&T Wireless account and make sure you have an active iPhone text plan. You can check this online and you should see a 200, 1500 or unlimited messaging plan on your account.
Assuming you are running firmware 3.0 or later, verify that your carrier file is updated. To check that the correct AT&T carrier file was installed, touch Settings -> General -> About. Next to Carrier your iPhone should say AT&T 5.5.
If this is not the case, follow these instructions to update your carrier file. Remember, after updating the carrier file with iTunes you must turn your iPhone off and reboot.
You have the correct carrier file but there are no MMS options available. Touch Settings -> Messages -> MMS Messaging and make sure MMS Messaging is ON.
Resending an MMS several times still fails. Try a hard reboot. Hold down the home and sleep buttons until the iPhone turns itself off. Turn the iPhone back on and try sending MMS messages now.
Still having problems? Navigate to your Settings. Touch Settings -> General -> Reset -> Reset Network Settings. After you reset your network settings the iPhone will reboot.
Some users have reported problems with the AT&T database, which required a call to the company or a visit to the store. It's possible your iPhone is listed as a first-generation iPhone if you owned one in the past. In this case, your device will not send MMS unless they update the database.