Occasionally, for various reasons, GitHub webhooks may stop working. After a while Buildkite (reasonably) stops trying to deliver to them.
Unfortunately this information is buried inside the Pipeline Settings > Github:
This is not the first place we logically look when this happens.
It’d be nice if there was some other indication in the UI that the webhook deliveries are failing and have been disabled. I think a UI hint would be sufficient, just a red circle that when you mouse over gives the details of the failure.