How can I recover a removed webhook from multiple stores?

I have a test app for pre-release testing. Recently it went down and the webhook was removed.

After reading about removing and re-adding webhooks, I deleted the webhook with the API and re-added for a store, but it is still marked as removed.

Does the webhook need to be removed from all stores then re-added for it work start working again? What exactly needs to be done to recover the webhook?

Not sure if this is related but the test app also brings up a 502 when trying to open in a dev store.