You attempted to initiate an outbound phone call, but the
Called phone number you supplied was not a valid phone number or was incorrectly formatted. Twilio accepts phone numbers in E164 format:
[+] [country code] [subscriber number including area code].
This error will also occur if you attempt to place a call or send a message from a Twilio phone number to itself (i.e. putting the same Twilio number in the
- The formatting of the 'To' number you supplied was invalid.
- You attempted to send a message or place a call from a Twilio number to itself.