Check if your User has all necessary permissions according to the role assigned.
Navigate to
Settings → User ManagementFind the User and check what role has been assigned to the User
Check Role Permissions by switching to "Roles" tab
Click on the pencil on the right
Go to Appointment Setting → Grant "Full" access
Events → Grant "Full" access
Schedule Events → Grant "Full" access
Your Closer/Setter will be able to add an outcome and once the outcome is approved, they will be able to schedule calls with leads.
Pro tips
In case you have a larger team, and you would like to grant more permissions to some of them, create a custom role, for granting them with all necessary permissions, while keeping other team members within their standard roles.