Hi,
retry period is for the same day you start your delivery e.g: if I started a delivery at 9 AM with 1h retry and max 5 ACS will retry to send failed at 10 AM, 11 AM, 12 PM, 1 PM, 2 PM
Plus you will have a retry every day until the end of delivery duration but ACS is limiting it to 3.5 days
Thanks,
David
David Kangni