Automation Not Firing

I'm attempting to develop on Automation for when someone logs in but it doesn't seem to be firing.

I'm listening to User.AfterAuthenticate, User.AfterIdentify, and User.AfterUpdate API Events. First, are these the correct ones to be listening for for when a user logs in? And is there a preferred one.

Secondly, I'm stripped my automation down to be as simple as possible. Literally just send me an email when someone logs in (I did this to test since it wasn't working).

core_v2_email.Send("Login", "Someone logged in", {
    ToEmail: ""
} );

I enable this automation and login but the email never comes. I've tested sending emails like this by using a scheduled automation and it sends, so why is are these API events not firing?