Privilege to search employee using VBCS template

We're using a VBCS Template to create requisition. And on requisition line, we need to provide the "Requester Email", and we used the "Get all employees" API to get the drop-down values, and we're able to see the default drop-down values.

But when we tried to search by the user name or email in the search bar, nothing returned. This only happens for certain user who are using custom job roles, but we don't know which privilege is missing in those roles.

We already added some privileged but it doesn't work.

Anyone knows which privilege that we need to add?