Inconsistent MIDI input

The way my MIDI keyboard interacts with MuseScore is inconsistent. Sometimes it works flawlessly, sometimes not.

For example, Yesterday I was working on a score, and used MIDI input without any issue. I then opened a new score without leaving MuseScore or MIDI and the new score did NOT accept MIDI input. This morning, when I opened that score, the MIDI input DID work for that particular score. Now I started yet another new score and the problem repeats itself.
I use Windows and my MIDI input has never suffered such interruption when using Sibelius.

Is this something unique (i.e. I am the only one) that suggest a connectivity issue between MuseScore and my keyboard?

Any input will be welcome.