When I debugged the application, I set the subscription lifetime to 1 hour. This time i did not change the time, there were subscriptions for 10 days with a callback from ngrok: http://f88f6b0c.ngrok.io/
The address after ngrok shutdown is not available. Generating the same domain is unlikely to succeed. Is there any way to unsubscribe? Or unsubscribe all subscriptions?
In the case of private data, such as channel subscriptions topic, you should also revoke the User Access Token if you no longer have access to the callback, and there is any potential for that url to be reused by other users.
For public topics you can just let them expire. Ideally though you shouldn’t use webhooks with callbacks that can be lost/changed during the lifetime of a subscription.