I have a date field in a SharePoint 2013 list that is marked as required. I need to update it to add the number of days in a payment terms field in a separate list. The target field is marked as required and set to date/time. When the workflow runs, it shows that it's been cancelled and the due date is not changed.
Note that this is a list migrated from 2012 Foundation to 2013 Enterprise. How do I remedy the above?