I'm trying to automatically set an issue's due date based on the following:
1. If the value of custom field "Departure Date" is more than 3 days away, then set the due date to now.plusDays(3) - since it can wait a little.
2. If the Departure Date is within 3 days from now, make the due date right now (because we gotta do stuff immediately).
I have scriptrunner but I'm new with it, so I'm trying to use Automation. I have an If statement checking JQL and that part seems to work, but its erroring out saying the Due date field may be unavailable for the project/type. I've checked in screens and in my field configuration and Due date is definitely in both, so not sure what to try now.

I've tried setting Due date as {{now}}, {{now.plusDays(3).abs}}, {{now.plusDays(3).format("MM/dd/yyyy")}} etc with no luck.