In previous versions of the KACE appliance, versions 5.5 and older, multiple email addresses could be saved in a USER PROFILE when they were separated by a comma. [example: "First_Last@mycompany.com, F_Last@mycompany.com" etc.]
In the updated versions of the KACE appliance this option is no longer available.
The option to save multiple email addresses is no longer available.
Use a single (desired & valid) email address for the USER to which all users need to be notified.