Motion 5 audio behavior

I have an still image that I want to make it dance with music. I used to do it easily with no problem, but recently when I want to drag my audio from audio tab to the Source Audio box in inspector, the audio does not move to the source. If I click on "To" and click on audio. I can see the graph,and I can play it , but it does apply t to any property of my clip. Thanks for your help, Talla