Currently, Sideline doesn't have the ability to send or receive messages to or from a short code (5-6 digit phone number). Unfortunately, this means Sideline isn't able to support most alert services which utilize a short code to send their messages, such as Facebook, Twitter, or other apps.
We are working on adding this feature in future versions, and appreciate your patience in this matter.
Please view our current list of feature suggestions or vote directly for this one on our Community Site. The more votes a feature receives, the higher it becomes prioritized! :)
If you have any questions about this, please let us know.