No violin sound after pressing N via MIDI keyboard?

Hi,

I'd need a quick help, I am totally newbie for Musescore.

I created a quartet template. My MIDI keyboard is working, and I can hear the violin sound perfectly.

Note entry from the computer keyboard work as expected, I can hear the violin sound when entering them.

BUT whenever I press the N to go into note entry mode, no notes are entered with the sound of the violin via the the MIDI keyboard, it gets muted (or does not get MIDI notes)! I press N again, exit from note entry mode and I can play the violin via MIDI.

What do I miss here? I'd like enter notes from the MIDI keyboard (sure I do know it is not real-time).

Please help!

SoosG.