Hi Kuba, thanks for your response. I solved the problem by using this solutio, see: https://github.com/BracketSpace/Notification/issues/260
btw: the version of php is 7.4.8
I solved the problem by adding do_action( 'notification/init' ) before the code for defining the class and the call for the function to register the trigger. But now I get an error from the notification.php-File. I will open another ticket therefore.
