Meta may show “Your pixel is being used on new domains” when it detects events from a domain it has not seen for that pixel before. Review the domain before allowing it; the warning alone does not prove that the traffic belongs to your event.
Check your event domain
Open your public event site and note the hostname in the address bar. This may be your event’s HeySummit subdomain or a custom domain. Compare it with the domain in Meta’s warning. Allow only domains you recognise and intend to use for this pixel. Adding the parent domain heysummit.com also allows its subdomains, so do not add it automatically for an event that uses a custom domain.
Review traffic permissions in Meta
Open Meta Events Manager > Data sources and select the relevant pixel.
Open Settings > Traffic permissions. Create or edit the appropriate allow list or block list. An allow list accepts events from listed domains and blocks others; a block list excludes listed domains.
For an allow list, add the event domain you have checked, continue with Next, then Confirm and Close. Keep any other legitimate domains using the same pixel.
You need permission to manage the pixel or the relevant business portfolio/ad account. Follow Meta’s current traffic-permission steps and explanation of new-domain notifications. Meta cannot recover events lost while a domain was blocked.