iphone SE accidentaly mutes itself

After updated to IOS 10 sometimes my iphone SE accidentaly mutes itself (no ringtone, no alerts, even no alarm!) but it has keyboard clicks and lock sound. It only goes back to normal after restart. Is there any solution for this issue? Everything else work normal mic is ok and it plays all sound for music or videos. But when someone is callinf or texting there is no sound for it.