How do I get the DUO auth key?

I enabled 2FA a while back, and at the time had DUO mobile set up on my phone. But since then, I've gotten a new phone, and re-installed DUO mobile, but it's asking for a key to authorize with TV. Plus, not I'm locked out of my TV account because I'm unable to enter a security code. 

So, how do I get a new DUO auth code if I cant log in to my account?