sun roof won't close and makes a rattling noise

Sun Roof won't open at first I thought I was pressing the wrong button. I kept pressing each button until it opened. When I tried to close it; it made a shuddering noise but only moved a little bit. I pressed to open it again, it made some weird noise. to short to describe, but when I press to close it again this time roof does not move and continue to make a stuttering/rattling noise.