Product: Programmable Voice
WARNING - 13512
Gather element has an invalid "language" attribute value
A Gather element has an invalid value for its "language" attribute. See the accepted language values list and update your Gather TwiML.
Your Gather TwiML has an invalid language attribute value. (Example:
en is an invalid value, but
en-US is a valid value.)
Find your preferred language in this list of accepted values and update your Gather TwiML accordingly.