Did you purchase the lappy directly from Dell or from a Big Box store? If from Dell, it may take up to ~14 days after the purchase before your Service Tag is activated in Dell's system. If you purchased from a Big Box, you need to register the Service Tag in your name to activate it.  Then see if there's anything helpful here and here...
I purchased McAfee livesafe 36 month with the purchse of a new laptop. The license on the laptop is 30 day trial. When I try to connect to Mcafee from icon taskbar I get a message saying no internet connection, which is incorrect since I am connected here. McAfee doesn't recognize the purchase on their home page because it was purchased here. I need the license information for this laptop, as well as other devices I wish to update McAfee on. I have now wasted half a day on this and office 365, so this is the last time I will be purchasing any extras when I buy a laptop or PC.
Purchased McAfee livesafe 36 month with purchase of new laptop.