Thank you for your message.
The error means that MIDITrail could not send the MIDI event to No.8 port,
because MIDITrail supports max 6 ports to MIDI OUT. (Port A,B,C,D,E,F)
However I think that MIDITrail should ignore the data and avoid clash.
I'm going to fix this bug.
Please check your MIDI data file, and reduse the number of ports up to 6.
Reply to #62533