The issues with Google Cloud Networking's load balancers have been resolved. Our apologies for any inconvenience that was caused.
Posted 5 months ago. Aug 30, 2017 - 21:14 UTC
Webhooks should be working now for all customers - we'll continue to monitor the situation.
Posted 5 months ago. Aug 30, 2017 - 17:02 UTC
Unfortunately Google Cloud Networking is experiencing issues that's causing some customer's webhooks to fail in Tracker. We'll continue to monitor the situation and provide updates to the status page. Our sincere apologies for the inconvenience meanwhile.