Why does my Apple ID login fail on certain platforms despite using a password manager?

Well it's pretty simple. I use a password manager. I have an apple id and a password. But I am constantly running into these asinine situations where the login and password for apple that I've had... the whole time. don't work through some modalities but do for others. For instance. I can login to apple tv using the apple tv app on my mac laptop fine. But if I try to login to apple tv on say, google chrome, on that same laptop, it fails, with an impressively abstruse error message. Why is this so stupid? Why am I here? Why doesn't authentication work? Why can't you recognize my identity? I'm so frustrated. Just write software that works. Just let people log in to their accounts.

[Re-Titled by Moderator]