Midi Issue For Newbie With A Midisport 8x8- Help! Options

[12xu]

I'm tearing my hair out here cause I cant figure out why one of my devices won't work in my Midisport 8x8/s. It's a Cheetah rack synth module, a lot older than my other gear. Everything else is working through the Midisport just fine and, if I use my Korg Triton as a midi controller direct to the Cheetah (without incorporating the Midisport) the messages are recieved fine. BUT- if I, for example, connect the Korg to Midi In 1 and the Cheetah to Midi Out 1 on the Midisport, there's nothing! Is there some other issue I can check, beyond the patchbay configuration on my laptop and the cables (all are fine)? Anything to do with it being an older bit of kit? Any ideas?!?! ANYONE?!?!