Custom Alert composer - not receiving email notification even its shows as sent

Summary:

Custom alert created for term employee

Filter condition:

${PersonNumber} = '25341'

${TerminationDate} IS NOT NULL

Recipient expression:

Manager Mail                ${AlertUtils.empManager(emps.PersonId).WorkEmail} --> Failed

Manager Worklist            ${AlertUtils.empManager(emps.PersonId).UserName} --> Failed

Employee Mail               ${emps.WorkEmail} --> Email shows as sent

Employee Worklist           ${emps.UserName}

Content (please ensure you mask any confidential information):

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

23D

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