The error is telling you that this.authState.email is undefined. It’s not valid to pass an undefined value to Realtime Database. You should check that before using it this way.

I’m seeing that you assigned this.authState from user in your constructor. Your logged user in the console, and it doesn’t have a property called email, so this error does not surprise me at all. But it does have a property also called user. So, perhaps you meant this.authState.user.email instead.