Manage Agent Groups with AD attributes

We want to add agents to a group according to a specific value on AD.

On Agent Groups > Manage Agent Attributes we added a new attributte ("carLicense" which exist on AD and will have value "01" or "00") and we want it to verify against all users without exceptions but the field "Search Filter" is mandatory.

If we write there only - (objectClass=User) - agent appears OK but group doesn't change from the default

If we write there - (&(objectClass=User)(uid=$LoggedinUser$)) - agent appears Warning with message "Agent group attribute discovery failure"

What is the correct way of filling this filter field? Or could the problem be elsewhere?

Thanks in advance.