Error: Twilio Error 21408

What's Causing This Error?

Error 21408 indicates that you have not yet enabled permission to send messages to the region indicated by the "To" number you are trying to send a message to. This setting ensures that you are not getting invoiced with unexpected charges and that you send SMS to regions only where you decide to operate.

Solution - Here's How To Resolve It

You have to enable permission to send SMS to the region in question by visiting the Geo-Permissions settings of your account.