It appears you can’t receive or send text messages with a Twilion phone number.  Read what the Twilio FAQ had to say about this.  That sucks, I hope they change it. twilio how to sms

No. Twilio toll free numbers are not able to send or receive SMS messages. When making an SMS app with Twilio, you must use an SMS-enabled phone number. This FAQ article has information on which phone numbers are SMS-enabled.