Automatic User Registration Email Hook

Hi,

I have a question about the automatic email that Gravity Forms sends out to new users after registration if that option has been ticked. I want to change the text of that standard WP email and therefore hooked into wp_new_user_notification_email. But that does now only work when a user has been created manually by an admin, not through the GF sign-up form.

What filter should I use instead for this to work?

Thanks!

All the best,
Christina