Postmen sent the events for each webhook URL with POST request.
If the webhook URL doesn't return a 200 HTTP response code, that POST request will be re-attempted up to 14 times in increasing intervals: 2^number_of_fail x 30s
- If the attempt fail, Postmen will retry the 2nd attempt 30s later.
- If the 5th attempts fail, Postmen retry the 6th attempt 960s later
- If the 14th attempts fail, Postmen retry not send out that webhook any more.