NIS 21.1.0.18 - Emails are not marked [Norton Anti Spam] - Outlook 2013

For a long time now I have been using NIS together with Outlook 2013 without any problems.  I simply set up a rule in Outllook 2013 for emails that include the words Norton Anti Spam in the subject that they are to be put into the junk mail folder.  Recently, I have been having problems with that, not because those emails are not moved to the proper folder....but rather because NIS has failed to mark them with the words "Norton Anti Spam".  I have tried various options concerning whether or not I have NIS integrated with Outlook or not and whether or not I have the Anti-Spam plugin activated in Outllook.  What happens is that sometimes it works properly but the very next time I open Outllook the emails fail to get marked even if I have not restarted the computer or anything else.

 

I just installed the latest version of NIS as noted above...with no change in the results.  I would appreciate any help on determining why NIS is not marking spam with the  "Norton Anti Spam"designation?

 

Thanks

FWIW, I used the Norton Remove and Reinstall Utility which installed the newest version - 21.0.2.1.  But still no joy....the same thing continues to happen.