I'm trying to use the v20.0 message_templates endpoint, but it is returning "Unsupported post request" messages, I selected the option to update my API from v19.0 to v20.0. I'm in doubt if the problem is the version of the API, or my account isn't verified?

I'm trying to use the request exactly like the "seasonal_promotion" example there is in the like: https://developers.facebook.com/docs/whatsapp/business-management-api/message-templates/components#example-requests