If Adobe I/O Events fails to receive a successful response code from your webhook within the configured timeout window, it retries the request, including a special header x-adobe-retry-count. This header indicates how many times the delivery of an event or a batch of events has been attempted.

Default webhooks: The timeout is 10 seconds.
Runtime Actions as webhooks: The timeout is 60 seconds.

Note: The timeout spans the entire delivery attempt, including the overhead of setting up the HTTP connection. This means that if your webhook handler responds in exactly 10 seconds (or 60 seconds for Runtime Actions), the delivery will still fail due to the additional overhead of setting up the connection.

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Please note that if an event delivery fails with a response status code of 429 Too Many Requests, or with any response status code in the range of 500 to 599 except for 505 HTTP Version Not Supported, then those events are retried. Events that fail with any other response status codes are not retried.

Adobe I/O Events will keep on retrying delivery to your webhook for 24 hours using exponential and fixed backoff strategies. The first retry is attempted after 1 minute and the period between retries doubles after each attempt, but is at most 15 minutes (see below table outlining the retry pattern).

Table
Retry Attempt	1	2	3	4	5	6	7	...
Retry After Interval	1m	2m	4m	8m	15m	15m	15m	...

Please note that above retry intervals are not guaranteed and may vary in few exception scenarios.

Adobe I/O Events changes the state of an event registration based on the below criteria:

UNSTABLE - Event registration is marked as unstable if, in the last 30 minutes, over 80% of at least 10 deliveries were unsuccessful.
DISABLED - Event registration is marked as disabled if, in the last 24 hours, over 80% of at least 10 deliveries were unsuccessful.
ACTIVE - Event registration is marked as active if, in the last 30 minutes, over 80% of at least 10 deliveries were successful.

For an Unstable event registration Adobe I/O Events still keeps on attempting delivery. This gives you sufficient time to restore your webhook, and avoid it from getting marked as Disabled. Once restored, it will be marked as Active on the next successful event delivery.

If all retry attempts get exhausted and the event still isn't delivered (webhook not responding or responding with a non 2XX response) or the registration is still in Unstable state, Adobe I/O Events drops the events, marks the event registration as Disabled, and stops sending any further events.

An email notification is sent to the admins of the organization when a webhook endpoint is marked as Unstable or Disabled.

Here you can see a sample email notification sent when a registration is marked as Unstable: Unstable Event Registration Email Notification

A similar email notification is sent when a registration is marked as Disabled.