Not sure what mechanicals are in your door...
If the stop was out or bad, your door glass would probably fall out of the regulator and not work at all..
If everything is new I would make sure you have the linkage lubed ( with a light grease ) and use some some dry powdered graphite ( not the liquid spray stuff in the can) in the channels that the glass rides in..
Could be kinda tight from being new... See if that helps..
Is your spring OK in your regulator?? It neutralizes the weight of the glass so you can roll it up....