I’m going to take a stab at this one. See if the MIDI Mongoose is sending CC#32 to the H9. That message is commonly used for MIDI Bank Select (LSB). CC#32 is the default MIDI binding for either Input or Output Level. You can change that to something else in the H9 … it’s easier in the H9 Control app. I’m thinking that a CC#32 value of 0 may have persisted through your power recycling, giving you nothing to hear at the output.
