Motorola Droid Turbo :: No Notification Sound When Getting Email

I have rebooted, contacted Verizon numerous times, been routed to a Level II technician, but nothing seems to solve the only intermittent problem of getting no notification sound when I get an email. The problem started out getting no ringtone sound when I got a call. Verizon finally fixed that by enabling something on advanced calling in their network. That took numerous trips to the Verizon store. Then, two days ago, I went back to Verizon with my wife to look at the iphone6 for her. I casually mentioned the notification problem to the salesperson, who said the problem was probably due to my downloaded sounds, and that I should stick to the sounds on the phone. I promptly went home and removed the downloaded sounds, but the problem persists. Because the problem is intermittent, no one has been able to fix it.