Proactive Web Messaging Notifications for Past Guests via Guest API

NICE CXone API & Integrations
1

Quick question about triggering proactive web messaging notifications for past guests. While my gRPC service reliably ingests /api/v2/conversations/messaging webhooks, pushing a follow-up via the Guest API fails. A simple POST to /api/v2/conversations/messaging/messages carrying {"toId": "guest_123"} immediately yields 403 Forbidden.

  1. Extract guestId from inbound payload.
  2. Authenticate endpoint call with service token.
  3. Observe 403 Forbidden.
    Which Web Messaging SDK function handles re-engagement for expired sessions?