Auto accompaniment on Yamaha psr i455

by chethan
(Bangalore, India)

Hi, Hope you are doing good. I'am trying to play the auto accompaniment on my keyboard, when I play the left most C the auto accompaniment starts but when there is a chord change the accompaniment does not change but only the chord is played, this does not happen on a casio keyboard. Any thoughts on it? Is there something wrong that I'm doing? or the Yamaha keyboard itself is that way?

P.S: I'm a newbie to keyboard.