Yes . I have an Airave, no bars without it. That does seem to be the problem, When I left my house this morning I could send text messages. My previous phone had no issues sending texts while connected to the Airave? Hope there is a solution or this phone will have to go back.
I had this same issue yesterday. The Sprint Rep I spoke to had me change the MSSD (?) number in my phone. Apparently, changing the phone caused "confusion" on my line because the new phone couldn't "recognize" how to/where to send text messages. I was able to send message to text messages to myself, but not to anyone else. After the rep had me reset that code in my phone, I was fine.