You might start all over with a factory reset, holding in the reset button for however long it takes (15 seconds?), and then starting from scratch with no encryption and no firewall.
If that doesn't work, then you might factory reset again, set it up for a wired connection, turn it off, carry it to the router, plug it into the router and start it up. (I'm thinking it will do its thing even if no one is watching.) Let it sit for a half hour, unplug it, take it back to the TV, and change it back to wireless.
If either of those get you farther, then you can start re-enabling your security.