Crazy freeze up with loud buzzing alarm sound?

[Andrew Highfield1]

Just happened to me on my OP3. Very disconcerting and no idea what was going on. Held power button for long time and phone eventually shut down. Then restarted and looks ok for now. Was streaming CNN via a VPN set to US IP at the time. Not sure if that or something else in background was going on. It's a strange one I have never heard about before.

 

[Vovkased]

I also have a buzzing sound that is loud. But it doesnt affect anything. It happens when i type/get notifications/press the back, home button
Can someone help me?
It happened on my tablet after i played a game. The version of my tablet is Android 7.0.

 

[Vovkased]

I tried even rebooting the tablet and muting it as my friend told, but nothing works!