Midi Thru not working?

I’ve got my Slim Phatty connected via USB with Cubases and that wroks all fine
now I want to connect a Jomox MBase through it’s Midi thru port, but no joy

in the midi settings I’ve got both Midi in DIN/USB enabled and BOTH to THRU
I can get signal via DIN MIDI OUT but MIDI thru just seems dead?
What am i doing wrong?

Try this see if you can just do a straight midi thru DIN from a MIDI DIN IN ( NO USB)

That way you can make sure your ports are ok.