NotePager Net says the message was sent, but it is never received on the pager, why?

If NotePager Net indicates that the message has been sent successfully, it means that the paging terminal has confirmed receipt of the message. If the message is not received, you may be out of your paging coverage area (or in a fringe area), your account may be incorrectly set up by the carrier, or you may have an incorrect ID/PIN number.