In order to receive the webhooks and avoid 403 errors, we highly recommend whitelisting our IPs and the URLs we send.
Our IPs are listed in our documentation. Check them out here!
The URLs that cause common problems with the firewalls are the trackingUrl and the picture_path_imgix. Please remember to add an exemption in your firewall for both fields if you subscribe to “Job update” and “delivery update” webhooks.