Webinar.chat_message_sent never fires while participant events deliver fine, DLP prerequisite?

We run lessons as Zoom webinars. We want to know that someone has spoken during a lesson while the lesson is still running, so a teacher can prompt a student who has gone quiet. We count messages per student and do not retain message content.

All other events (meeting joined and left) are subscribed on the same Server-to-Server OAuth app, pointing at the same HTTPS endpoint. The participant events work end to end. The chat events have never arrived.

  • webinar:read:chat_message:admin is granted.
  • Not the endpoint, signature or subscription — other events on the same subscription deliver and are processed.
  • The messages that produced nothing were sent by the host and a panelist to everyone, not by attendees.
  • “Enable external in-meeting chat DLP integration” is enabled on our account. We understand this is the reciprocal setting — it applies other organisations’ policies
    to their users and is not the one required here.

Several threads here point to DLP as the prerequisite, and in one thread a poster confirmed webhooks began arriving after DLP was enabled via Account Settings →
Meeting (Advanced).

We raised a support ticket asking for this and it was closed as “configuration-related and not within the scope of your Developer Support Plan”, with a referral to
this forum. So:

  1. Is DLP still the prerequisite for webinar.chat_message_sent in 2026?
  2. If it is, what is the correct route to get it enabled, given Technical Support declined the request as out of scope? Every prior thread ends with “raise a support
    ticket”, which is the door we’ve just been shown out of.
  3. Does the requirement differ between the webinar and meeting variants?