Step one: the Studio flow routes incoming WhatsApp messages through a SNIPPET action to parse the wa_id before handing off to our internal routing API, but the REST Proxy endpoint at POST /api/v2/integrations/webhooks/inbound keeps throwing a 422 Unprocessable Entity with {"errors":[{"code":"INVALID_PAYLOAD","message":"Missing required field: messaging_type"}]}. The London edge runs CXone 24.06, and the request body definitely includes "messaging_type": "text" right before the proxy handshake, but it’s still choking on the validation step. Console logs just show ERR_PROXY_TIMEOUT after exactly 3000ms. Doing jack all with the retry logic since the gateway drops it hard.