We haven two Samsung TVs connected to Xfinity cable. Both work fine, we stream various stations. I was attempting to use an app on the TV we'd never used before (without success) and clicked on the gear icon for Samsung; sign into Samsung on the TV popped up. I tried to login, of course none of my emails or passwords worked.
I have a Samsung phone and Samsung notebook. They are on different email accounts, different passwords, etc. (I didn't do that on purpose!!)
Is there any reason I should sign into, or set up an account on the TV? Do I need a separate password for every Samsung device I own?
There is not, a single account should work on all devices. If you are unable to sign in, I would recommend checking your internet connection, check for software updates and if you still have issues, try a factory reset of the television.