Event Alert - is not sending out emails to employees

Summary:

Event Alert to Employees - what is the correct expression

Content (required):

Event alert need to be send to all employees. Added recipient

Communication Method:

Mail, with expression ${AlertUtils.person(emps.PersonId).WorkEmail}

Worklist, with expression ${emps.UserName}.

However emails are not being send to employees work addresses.

Please be so kind as to assist with where we are going wrong?

Version (include the version you are using, if applicable):

21C

Code Snippet (add any code snippets that support your topic, if applicable):