In case the original notification sending attempt fails (due to receiving a non-2xx response code or exceeding timeout of 10 seconds), we will try 3 more times : after 3, 30 and 150 seconds. If it still fails for each of those attempts, it is counted as one non-successful delivery.
We’ve seen a couple of cases where webhooks failed to be delivered. One such case was caused by a 3-minute downtime in our database; others we suspect have been caused by failures in the network path between Pipedrive’s servers and our’s, since there’s absolutely no record of the request in our servers.
Obtain a log of non-successful deliveries
The only way to obtain this log is by contacting our support engineers I’m afraid
To retry them
Other than the retries we will already do, no there isn’t
To increase the number of attempts
and/or
To increase the delay between attempts
For the last 2 points, these also aren’t possible currently as there hasn’t really been requests to increase either - but we monitor this closely and if it turns out to be useful for others we may try to implement this.
Please please please make an API endpoint to get this kind of data
You have a very nice support team, but contacting them every time seems like such a waste of time for both parties.
Edit: Also, would be very useful for even successful deliveries, if you need to replay past updates, for whatever reason.