Message Send Failure

I'll assume that you are talking about an SMS message? You have activated the phone, do you show service? If you do, how many people are you trying to send the message to? When you say message send failure, is it displaying the exclamation point in the red circle? If so, have you tried to resend from that? If you have and it isn't going through, you can try a reset on the phone, that is holding the power button and the home button together until you see the Apple logo, ignoring the slide to power off screen. This does not have an affect on data. If that doesn't help, you might want to check with your carrier to make sure your account is provisioned correctly. Failures to send are generally a carrier issue.

If you have done a reset and it hasn't fixed it, I would be inclined to believe it has to do with the carrier. Most software issues, especially on a new phone like you describe, can be taken care of with a reset. Call the carrier and have them check your account. They should be able to send and receive test messages while on the phone with them. Call from another phone if you can so you can follow their troubleshooting.

I have had that problem before. I hypothesized a way to fixed it, tried it, and I havn't had a problem since then. The way that I stoppe the problem for me is I went to Settings -> Messages -> "Show Subject Field" -> OFF.

My hypothesis for the problem was that the person that I was sending the SMS to did not have a phone that supported the "subject line" feature. So the message to the persons' phone would bounce back, since the phone did not support the feature, because the iPhone is of superior technology, and that the persons' phones' technology is insuffeicient for the mighty hi-tech Apples iPhone.

Before I started using an iPhone, I had a Samsung U900. My friend had an iPhone, and she had the show subject line on. When she sent me an SMS, the error would come up on her screen. When I changed to the iPhone, she can SMS me as normal.