Unwanted alert sound I have a Samsung Galaxy 8.Every 5 minutes or so I hear my phone buzz then I hear a gong sound. This gong sound is driving crazy.

Here is what i tried:

1: restarted my phone

2: killed all applictions

3: Ran a good antivirus 

Also every time this song comes, if im watching a video on YouTube It causes to pause.

Any ideas?
sounds like (no pun intended!) you have notifications set to alert you.  Do the sounds coincide with email delivery, twitter alerts, Facebook alerts etc.  You can probably check notifications in Android Settings.  I don't know about Samsung but on my HTC running OREO the notifications are under Settings/Personalise.

If this doesn't help I suggest you edit your original post to include the Android version that you are running - see Settings/About/Software Information.