Mazda 3/Axela HEV 2014 problematic chime played repeatedly
 

This is a Mazda 3/Axela skyactive hybrid vehicle of 2014 and it has been running smoothly with no problems. However now a certain chime plays repeatedly when travelling at speeds below 50km/h. It is the same chime that plays when u ignite the vehicle and when u go over a bump. It even plays time to time when the car is in idle mode.
What could be the reason ? What should I do ?