Did you add water to it? If not add 4oz of water to it and try another coat. It will give you time to get rid of any roller marks. Also, have a light shining on the scren are off to one side. That will help you to see the roller marks. When you're done applying go over it once more top to bottom with the roller. Apply no pressure and over lap each row an inch or two.
If you have enough water and you do this, the roller marks should be gone!
mech