Help me understand why this expression isn't ...

[Steven_Jeffery]

Help me understand why this expression isn’t working?

NOT(useremail() = "stevenjgunvaldson@gmail.com")

I have this expression in my UX view Showif constraint.

What I am asking the App to do is: If ‘stevenjgunvaldson@gmail.com’ is signed in, DO NOT show me this view.

Though if anyone else is signed in, show me this view.

Am I doing something wrong, because it is not working?