I have a Samsung J7 phone. When i turn on bluetooth to connect to anything, I continually get a notification sound about every minute even after making the connection. So the result is that I have to turn bluetooth back off to keep from getting the notification sound. I have gone thru and turned off notifications for all apps. I have blocked notifications for as many apps as I could. When I get these notification sounds, there are no notifications listed. If i leave bluetooth on so it is connected to my car, headphones, watch etc. I get the notification sound about every minute, so unless I am doing something like downloading from my watch I get the sound every minute as long as bluetooth is turned on.