I used AUX 501 and 502 to create IR devices in the MX-900 editor, imported them into the MSC-400, and converted the devices into a smart macro group. But something's not right, as the macros don't seem to transmit anything. I tried both quick testing from the editor, and also actual remote triggers (since the quick testing is a bit flaky), but no cigar.

I checked that the MSC-400 is recognized as a keyboard device in the computer in which it's plugged. The USB2 light is on. The status light flickers when I try to transmit a keyboard command, either from the editor or from the remote. But it's not doing anything on the PC itself.

What did I forget?