Originally Posted by rangercaptain
I thought Canadians were polite . . . Amigo, you're just offering your opinion, but I just went through this with at&t for my sister-in-law. She had an old HTC flipphone and wanted my HTC smartphone with a great keyboard. We put her old sim in and got that error code. We went to an at&t corporate store, and they gave us a new sim and we left with a working phone. After a day of using it she got a text message saying a two gig data plan was required. When she didn't acknowledge that, they cut off the account.
The sim was free. Don't tell me I'm wrong when you don't really know what you're talking about.
The two posts following yours confirmed what I was originally saying sir, and quite frankly I do know what I'm talking about. I work ICT for a North American wide company and regularly travel to the states supporting events that require this kind of connectivity.
As for you're sister in law, she probably got that message because a background app was attempting to use data, and it wasn't disabled on the phone, thus the text. This I have also encountered.
Back on topic, I agree there may be a network outage in your area. But if all else fails a visit to the AT&T store can't hurt. Worst case scenario just sell the note on Craig list