If your sliding shower door gets stuck or is not moving as freely as it should, you should move quickly to repair it to avoid further damages. Start by checking the rollers to see if any of them has slipped off its track. If so, lift the door and guide the rollers back. If that doesn’t solve the problem, remove the plastic guide, and then remove the shower door from the tracks. Test the rollers. If they don’t roll smoothly, apply a silicone spray lubricant. If this does not solve the problem, then you will need to replace the rollers and work on the alignment.