Sunroof goes up not open

[NewbWrench]

I'm going to start a new thread because I see a lot of tilt or stuck open options but not what's happening to me. My sunroof will tilt all the way open just fine but when I push the button to open it to slide backwards it sinks down and starts to slide and then goes maybe a quarter of an inch back and won't go any further. Is this a drive cable or belt issue?