I am guessing you are using dhcp for the SM's once they connect to the tower, since you are not accessing it via a static address you have pre-assigned to the unit?
If so, this is going to happen since ALL units have the back door address of 169.254.1.1.
You will need to look at the wireless tab of the AP it connected to or router table (depending on how things are set up) and use the dhcp address assigned to that SM. Then you can access it.