Same problem here, but only on email app. SMS app works fine, sound played when sms arrived
Volume maxed on all 4 component - ringtone, media, notifications, system.
In Notfication mail app is on, on more settings email is on for Allow Notification, on more setting again i see my amail accounts and a ring tone for every account and every acount has notofication on + vibrate.
No sound an d no vibrate, no matter waht account receive mail.
This problem is not solved by ressetings to factory settings. I did a factory settings reset and first i tryed this mail app, did not working.
Very annoying.
Any solution welcomed
Damien solution "Swipe down your notification bar and click "notification settings" Then click "advanced" in the top right corner -> click "more" in top right corner -> finally click "reset app preferences" - did not worked for me
Later Edit - think is a bug , at every 10-15 mails received on the same account maybe one will play notification sound....
I find a workaround, but not very convenient. I put all mai mail accounts on gmail app. When mail received this app will sound and i go to email app.
S7 Edge no sound notification text, email etc....