REV23 Desktop previously sent text messages by emailing the customer’s mobile number through their carrier’s SMS gateway (for example, an email to 5555555555@txt.att.net). Because of carrier A2P 10DLC requirements, this method no longer works and REV23 Desktop can no longer send text messages. See Text messaging in REV23 Desktop for the full explanation.
Text messaging is fully supported in REV23 Cloud, where the A2P 10DLC registration and opt-out requirements are already handled for you.