
0r1v2 (0r1v2) asked a question.
The event hook seems to be configured correctly to an AWS API Endpoint.
This endpoint can pass events with no issue. The configuration is using the correct API endpoint and api token. I am not sure why we are getting the following error.
Event Hook Delivery Failed
FAILURE: 500 ServerError. Exceeded maximum retry limit of 1

Perhaps a timeout issue. "Note: Ensure that your external service can send responses to requests from Okta within the 3-second timeout limit." https://developer.okta.com/docs/concepts/event-hooks/#timeout-and-retry
Found old post with similar error.
https://devforum.okta.com/t/delivery-failed-for-event-hook/12628
@0r1v2 (0r1v2) - Matthew is likely correct. Typically you want to make the second card in the flow an HTTP close (200) to inform the event hook delivery that it was received. Otherwise it won't respond until after flow processing occurs. This sometimes will result in a redelivery of the same payload and 2 Flow execution with the same exact event. Sending the close usually prevents the problem.