"This is spam" button not working

When I click Norton Internet Security's "This is spam" button, a popup invites me to send the offending email message to Norton. I click the "Yes, send this email (Recommended)" button and also check the box to "Use this action for all misclassified emails". Problem: Once I have done that, why does Norton's "This is spam" button thereafter always ask me again whether I want to send the email to Norton? How can I get Norton to send the misclassified email to Norton always, without repeatedly asking permission?

I use Outlook 2013.