Linking not supported for whatsapp sandbox integrations
I'm trying to follow this guide to start business initiated conversation in WhatsApp. I successfully created the user in the first step, but I cannot link it to the WhatsApp channel.
I'm calling API POST request:
https://api.smooch.io/v1.1/apps/{myAppID}/appusers/{myUserID}/channels
With body:
{ "type":"whatsapp", "confirmation":{"type":"immediate"}, "phoneNumber":"phoneNumberInInternationalFormat" }
But result is:
{ "error": { "code": "bad_request", "description": "Linking not supported for whatsapp sandbox integrations." } }
So my question - is there any way to send a message using Sandbox number, or I need to register a number by requesting access process?