just purchased 65" 7000 series tv at best buy. Rep said it had you tube tv. It apparently does not. I can download from internet to tv. I can log in but won't play live tv? Really? Say it isn't so Samsung. I just ditched a 65" 8600 series from 2015 as the dedicated smart hub kept failing.
Can you provide me with your full model code? This may sound silly but have you checked the App Store to see if the app is available to be downloaded? (See the link below) Is the TV connected to a soundbar? If so, how is it connected? Are you trying to play YouTube through a Bluetooth device or through the TV?