There are several possible reasons that this error message is generated. From the WiSM's perspective, the most common reason is an incorrect configuration of the service port on the Supervisor Engine.
In the case of a WiSM, the service port is used solely for communication between the Supervisor 720 and the WiSM.
Complete these steps in order to get rid of this error message.
Create a new VLAN for the WiSM service ports on the Supervisor Engine that does not exist anywhere on the network.
Create a DHCP scope setup on your Supervisor 720 to assign IP addresses to the service ports of the controllers. This IP range should not start with the same octet of any interface that already exists on your network .
Note: It is recommended that you create a DHCP scope for the service port of the Catalyst WiSM. Alternatively, you can also session (session slot X process 1 or 2 ) or console directly into the WiSM and set the static IP addresses (configure the interface address service port).
Assign the WiSM service ports to this newly created VLAN with the command wism service-vlan new VLAN ID on the Supervisor Engine.