nighthawk R8500

I received emails to update my firmware and when I click on the links or try to go the the web address separately, I keep getting an error saying y devide is not connected to the wifi network.  I have cleared the browsing history as it suggested and it still does not work.  It is the only computer I have and I can get on any other websites......how can I not be connected and what else can I do to perform these updates?