Error message - CMK Config not connecting with the keyboards

There are only a couple of reasons why you would be getting that message:

1) The MIDI in and MIDI out from the keyboard are reversed at the interface

2) A bad cable somewhere in the chain

3) One or more of the keyboards is not connected to power

4) Your device has not been selected in CMK config's MIDI in and MIDI out configuration screen

5) The MIDI out from the MIDI interface has not been connected to the stack so there is no MIDI loop between the computer and the stack