Line manager is unable to search incumbent and internal candidates in Succession plan

We are trying to enable succession plan functionality for Line manager and we are unable to search/view employees in incumbent and Internal candidate drop down.

We have added below privileges to the line manager role

• Manage Succession Plan – Functional Security Policy

• Report Succession Plan Candidacy, Report Succession Plan Incumbent, View Succession Plan Candidate, View Succession Plan, Add Worker to Succession Plan, Create Succession Plan for Worker – Data Security Policy

• Create Succession Plan for Worker, Edit Succession Plan and Manage Candidates , Succession Plan Management – Role Hierarchy

Could you please help us here if we are missing any other privileges to make the succession plan functionality works for line manager.