What Internet connection do you have going to the TV?
And what happens when you go through the set up procedure in the Vizio menu?
If all other Internet functions are OK and your set is supposed to come with the Netflix app and it doesn't connect, that's the only thing it could be. But Vizio has issued firmware patches for various issues with their sets, but of course, they are model specific. So get back with the model number and I'll see what I can find out.
Just go to the Vizio web site, click on Support and Downloads and it should be there, if there is any for your set, and the instructions for how to do it should be there.
If it turns out that there is no firmware update, and if you bought this TV locally, I would suggest taking it back for a new one or arranging for a warranty service call. If it's supposed to connect to Netflix and it won't (and your Internet is OK, which clearly it is), then this should totally be covered under warranty.
Let me know if you have any other questions, and thanks for using JustAnswer!