Unknown reason for ding-dong sound.

[AC Question]

I currently have an S5 and a Motorola before this. They both make/made a ding-dog sound at the same time every evening. I have tried everything I can think of to fix it and keep coming up short. It's not an alarm or a calendar setting. Any help at all would be greatly appreciated.

 

[Tim1954]

Sound like a repeat notification /reminder. Have a peek in accessibility for notifications reminders....