Midi output lost from DAW to Krome

[Phil C]

I use Reaper as my DAW with my Krome workstation. Every session, I find that at some point, midi tracks recorded into Reaper from the Krome suddenly don't play back. That is to say that everything looks normal - I get the midi out indicator in Reaper, the transport moves normally etc, but the Krome just doesn't seem to receive the midi message to play the notes. I have upgraded all my midi cables, minimised their lengths etc to no avail. I haven't yet found a common trigger for when this happens, but I'm still looking. The only fix I have found is to reboot the Krome and restart Reaper - this is okay as a workaround but very inconvenient. Do you have any ideas?