13226: Dial: Invalid country code

You receive this warning when the phone number passed to <Dial> uses a country code that Twilio cannot identify. Destination numbers in <Dial><Number> should be valid phone numbers in E.164 format with a + and country code.

• The value inside <Dial><Number> is not in E.164 format and does not include a recognizable country code.
• The number starts with an invalid country code, or it begins with 0, which is not a valid first digit for an E.164 country code.
• An international destination was entered in local or national format instead of + followed by the country code and subscriber number. (help.twilio.com)

• Format the destination number in E.164 before you return <Dial> TwiML. Include +, a valid country code, the area code or national destination code, and the subscriber number. Keep the total length to 15 digits or fewer.
• If you are converting a local number to E.164, remove any national trunk prefix such as a leading 0 before adding the country code when required for that country. (help.twilio.com)
• Validate and normalize phone numbers with Twilio Lookup before you place the call or generate <Dial><Number>. Lookup can validate formatting and return invalid country code errors during validation.
• If you are not dialing a PSTN phone number, use the correct <Dial> noun. Use <Client> for a Voice SDK identity or <Sip> for a SIP endpoint instead of <Number>.

• TwiML Voice: <Number>
• What is E.164?
• Lookup v2 API