iTunes Store blocked by NIS - I confirmed this by turning off Firewall and was able to connect

I have tried everything that was suggested on the Norton Forum clear back to 2010 and everything suggested by Apple Support.  I have done everything I know.  I do know that when I turn off the NIS Firewall,  the iTunes Store opens and is accessible so it is a setting on my computer.  I have tested with another user and the same thing happens.  I am at a loss.  Pulling my hair and I don't have much left...a little humor remains entact.  Please help!

 

Mur