Had it working, now it stopped. AT&T has the right IMEI info and all is provisioned okay on their end.
I am able to receive MMS messages but for whatever reason cannot send using Go SMS Pro. Lady at AT&T send me an MMS while we we're on the phone. She asked me to try and send, so I tried to send a pic to my sister and after about 1-2 minutes of it trying to send, I get a message in the notification drop down, that message was unable to be sent. Mind you texting works flawlessly. I wrote to them and awaiting a response. My APN matches that of what was posted above.
I don't know what else to do at this point. Can anyone help?