magenta does not return in real time (no sound)

[yakiyaku]

Even if I play the melody, the sound that magenata returns does not sound, but the MIDI data downloaded after playing confirms that the sound is arranged.

I want magenta to return me even if I play the melody like the following site.
(https://www.youtube.com/watch?v=owOI2CMavoE)

If you can find out why the sound doesn't sound, please give me a professor.