Is this at night when pointing at the sky or during the day? If at night, try the camera during the day and then try to focus on a remote object (apartment block, sky scraper, church, mountain). Then try at night. If the camera is not close to the focal point of the telescope then only noise is displayed. Anywhere near and you should see larger or smaller disks representing unfocused stars but as soon as you are too far off those rings become very large and faint so you won't see them anymore.
