1. Do you have installed our app in some of your ServiceNow instance.
2. Is the instance added to NPM?
3. Do you have Alert Action created?
Do you have only one Short Description in ServiceNow? If more you can try find more properties when you click "Select properties" in action definition.
If Short description still not populated don't hesitate create support case and put number here.
Thanks a lot
If you have in ServiceNow Short Description as list of definitions it will show you the same in NPM. Can you put Custom Value to Short Description in ServiceNow? Which type is Short description field
Doesn't you have any other Short Description or similar text field in ServiceNow? You can add any field from incident with "Select properties" button in definition of action.
Cause of problem is a relational dependencies between list and Short Description Item in Service-Now. You have to delete all items in list (issue with a web page, Issue with email, Issue with networking, etc.) in Service-Now. If you delete an items then you can insert a custom variable.