approver field is empty not showing any names

[Sukanth GC]

I'm trying to add the approval process and I've setup the approval workflow. But when I try to select an approver no names show up in the field. But, I'm able to add people in other fields like Request participants.
I have checked and the field is configured to be user picker (multiple users)
How should make the names pop up in the approvers field?

[Dave Mathijs]

Hi @Sukanth GC , are other people or is anybody able to see users in that field?

[Sukanth GC]

Hey there @Dave Mathijs 
Nobody is able to see other people in that field!