I've seen this before.. angle the piece's end into the plank previous, and bring the plank downward to floor. Now angle both joined planks into the last row installed, then apply little pressure downward to click the pieces together. Try using light patting with hand to the surface of row you are installing, and this works well to close up the gap. I have found that inadequate acclimation will make installation much more difficult. Allow 48 hours with the boxes inside the room (project) before you start to install. Hope this helps.
