LR seems to be failing on some iphone video - "Connecting to Dynamic Link server failed"

I noticed in one of my folders that the few video files that were in there would not play. Their thumbnails in grid view were gray as if they had no preview, and the icon just spins and spins when i hover over it waiting for a preview to load. files wont play either. i removed them from the catalog and then tried to synchronize the folder and I got this error message saying an "unknown error has occurred"