I am so sorry it took me so long to respond. I have moved this question to a more appropriate forum. But my best guess as to why you are not able to send SMS is because you have not gone through our TCR process which is necessary prior to being about to send. You can receive, but sending requires some due diligence first. 

Hi ​@lawyervince, if you need any help with TCR Registration, feel free to send me a DM. I’ll be happy to assist you!