Issue

When attempting to add a phone number to your account as a verified caller ID via SMS you received the error:  "The verification has been blocked as this is a restricted country for verifying a caller ID by SMS"

Product

Phone Numbers

Cause

You have attempted to validate a phone number via SMS for a country which is not permitted to be validate by SMS.

Resolution

Validate the phone number via call. See How to Add and Remove a Verified Phone Number or Caller ID with Twilio