## Warning - 13224
This error occurs when the provided number is not in E.164 format; for example using local dialing pattern 01234567890 instead of the full E.164 address +441234567890. This can also occur when calls are attempted to non-existent country codes, area codes, or exchanges. For example, there is no +693 country code, no +1238 US area code, and no 555 US exchange.
This can also occur with properly-formatted, valid destinations if none of Twilio’s carrier partners are able to deliver the call; for example a telecom network outage in the phone number’s local area.
Use E.164 formatting and ensure the destination is a valid, in-service destination.