Device Host information not correct

• For testing APIC-EM discovered a location with 7 * 2960X Switches + 3750X core. It seems that the Host information on the discovered switches is wrong.  For example: APIC-EM show that 4 Hosts are connected to a switch but 24 ports are up But unable to find Host PC nor other devices connected to the switch plus 3 Meraki AP´s connected but the IP is not visible in APIC-EM.. What causes this behavior.
•  using IOS Version 152-2a.E1
• APIC-EM version 1.1.0.767

The controller uses ip device tracking to pick up hosts. you should see the hosts that appear in "show ip device tracking all" in the host inventory. Can you ensure that device tracking is enabled.

Need to enable "ip device tracking Maximum {} on per Interface Basis to activate IP Device Tracking on 2960S Switches.