Approve Job Offer : An attribute in the BlueCollarPermanentV1 rule has a null value

Hello everyone,

The job offer has been sent for approval to the applicant named KM.
The transaction has failed and this is the issue description : " An attribute in the BlueCollarPermanentV1 rule has a null value "
Here is the resolution : " Ensure that a value is entered for the mandatory attribute used in the rule configuration or add a not null condition for this attribute "
Could someone explain me what do we have to check or to do to recover this job offer approval please ?

Kind regards