Windows 10: Mysterious notification sound

Hello. Since this afternoon, I'm having the System notify sound of Windows, with no reason. Notification center is empty.
Where can I see what is happening?
It's the sound at 2:55 in this video, called "Windows Notify System Generic" [youtube]K5ARPC-FTHo[/youtube]

:)

 

Understanding sounds

I have a new Microsoft 950 phone, with Windows 10. From time to time it emits a notification sound that I do not recognise, with no indication on the home screen of what is being notified. I am trying to work out what the sound indicates.

The problem is that when I go into the Settings > Sounds > Notification menu, there seems to be no way of playing the default sounds. With all the other sounds, there is an arrow beside the sound, and if you tap that, the phone gives you a sample of the
sound. But when you have the default sound set, there is a check mark next to it, not an arrow, and it does not play a sample.

I had hoped to do down the list of notification sounds set in my telephone, to find the one that sounds like the mystery notification. Any idea how I can do that?

 

Sky Force Notifications after ANNA update! whats that?

that notification application looks mysterious and yes it is not related to notifications widget on homescreen!

 

Settings / System / Notifications & Actions ... under Get notifications form these senders, check to see if one of them has only Sound enable. You can Click on each one to see the Notifications Options available.