Apple TV won't accept ID & password

I have had to restart my Apple TV (which I have had for years) and now it will not accept my Apple ID and password. I have reset it to factory settings, checked the network settings, every setting I can think of and nothing seems to fix it. Every time I enter the ID and password it tells me that either the ID can not be found or the password is wrong but an alert gets sent to my phone telling me a device is trying to log in using my account and do I want to allow it - I say yes and get the verification code and still I can not log in. Can anybody please tell me where I am going wrong??? I know the id and passwords are correct because they work on my other devices and I get the alert! Very frustrating. Very much appreciate any help.