I am afraid I have found a bug:
I used different triggers, just one didn't work.
new user > e-mail arived, notification log > ok
page published > no e-mail arived, notification Log > empty
page edited > e-mail arived, notification log > ok
Wordpress Version 5.6
PHP 7.4
Elementor
The new pages are generated by filling out a ACF frontend form
https://ttclub.angelink.ch/einfuehrung-ttclub/
After registration the user fills out the ACF Frontend Form. After saving/publishing his page he can edit it.
Triggers for new registration and edit work fine, but not the published new page.