I have found that the MIDI out messages (all, including SysEx and notes) is not received on the iConnectivity Mio10 (which I use a distributor across my stage setup (2 synths, a harmonizer, a digital mixer, video triggering etc.). Mio10 is not receiving any midi from the uTrack24, not from any port.
There is nothing wrong with the Mio10, it receives MIDI from all other devices in my setup.
Connecting the uTrack24 straight to a synthesizer, showed that the uTrack is actually sending MIDI and it is received on the synth. Putting a Roland A-880 Midi Patchbay in between the uTrack24 and the Mio10 solved this issue, but it remains a question why the Mio10 cannot receive the MIDI data straight from the uTrack24.
Question: Could it be that the ground pin has been disconnected in the uTrack24?
I think the Roland A-880 and the Synths I am using (Roland and Korg) add a ground connection to all MIDI ports on its own, and the Mio10 does not have that hardware feature.