Getting 'Please remove the invalid approver' error in AME

I am getting the following error in AME -

Error : ORA-20215: An invalid approver has been encountered in ame_engine.fetchRuntimeGroup:AHLM_ABS_FYI_EXPAT. Please remove the invalid approver. Invalid approver originating system person_id and originating system ID 8904.

The definition of  the approver group AHLM_ABS_FYI_EXPAT is

select 'person_id:'||xxame_my_pkg.ssa_get_functional_spv(:transactionId) from dual

The above query returns the person_id 8904

But the employee with person_id 8904 is an active employee

When I query

select * from per_all_people_f

where person_id= 8904

and trunc(sysdate) between effective_start_date and effective_end_date