60331: Locale requested is not supported by Verify Text-To-Speech conversion

Twilio returns this error when your Verify request includes a locale for voice delivery that Twilio cannot convert with Text-to-Speech. For Verify call channel verifications, Twilio can resolve the language automatically from the destination phone number. If you send an unsupported locale override, update it to a supported value or remove it so Twilio can apply the default language selection and fallback behavior.

• Your Verification request included a locale override that is not supported for Verify voice delivery.
• The locale value does not match a supported Verify language tag for the Voice channel.
• The requested spoken locale is not available for Twilio Text-to-Speech. Twilio requires supported language values for synthesized speech.
• If you use a pre-approved template, the requested language is not available for that template. Pre-approved templates support only a subset of Verify languages.
• If you use a custom template, the required translation for the requested locale has not been provided.

• Remove the locale parameter and retry the verification. Twilio will resolve the language from the phone number country code and fall back to English or the template default translation when needed.
• Set locale to a supported value from the Verify supported languages list. For voice delivery, confirm that the locale is available for the Voice channel.
• If you need a specific spoken locale, verify that Twilio Text-to-Speech supports that language and locale before you send the verification.
• If you use a pre-approved or custom template, confirm that the template type supports the requested locale and that the required translations are available.

• Verify supported languages
• Verifications API reference
• Text-to-Speech (TTS)