What you need to do is go to your Twilio console, to the Geographic permissions for SMS section and ensure you have the permission checked for sending to the US.
As I m facing the same issue "Permission to send an SMS has not been enabled for the region indicated by the \'To\ number", then I enabled all the regions and it worked perfectly
If you are using it for registration process consider using their "verify" service which allows international phone numbers instead of the "programmable sms". Otherwise you have to manually enable the countries.