My iphone 4 won't work with my stero?

I have a sony stero w/ ipod/iphone doc i hit the ipod button but i don't get any sound at all, if i put it radio on i get sound so its not the stero. How can i fix this

And good afternoon! My name is Amanda Maffei here with the Sony Support team. We're very sorry to hear that you're having issues with the iPhone/iPod dock. I would recommend trying our esupport website by clicking this link: www.esupport.sony.com. You can type in the search bar the full model number, and there will be some troubleshooting tips and how-to's that might fix the issue that you're having. And if you can't find a solution through there, please contact our Technical Support team by calling: Priority Service: 239-768-7679. We hope this helps!