This error usually occurs when the applicant number is not linked with their personnel numbers.
Please link the personnel number with their applicant number.
In Back-office:
Go to Core personnel, Recruitment, Recruitment maintenance, Applicant details
Search applicant number
Double-click on the record
Click on the Link button and click on Match against the correct personnel no
Click OK
In Portal:
Go to Recruitment Dashboard, Applicants
Search applicant and click on the View button
Under the applicant details tab, click on the Applicant Link button in the top right corner
Under the Employee link enter the personnel number
This will link the employee