Nighthawk 2.4 isn’t showing up but looks to be working on nighthawk. Any ideas how to fix it?

What router do you have? 

You say its not working but looks to be working on the nighthawk? Do you mean its showing enabled on the online browser?
What firmware version are you on? 

Does it have smart connect? (smart connect combines the 2x ssids if you have a dual/triple band device)