Activating Microsoft Office 365

I just bought a subscription to Office 365.  I keep getting an error message that it can't activate.  There's a timelimit on using it without activation so I'll be out he cost of the subscription if I can't solve this problem.  Plus losing email, etc.  I do see that sometimes anti-virus software can be causing this problem.  Is there a way to temporarily turn off Norton to see if Office 365 can be activated?  If so, I hope I don't have to leave it turned off and go through it every time I restart the computer.