Ice maker leaking down back of fridge

I am a new homeowner and therefore new to appliance repair, always nice having the maintenance guy come at the apartment. Anyway I own a Whirlpool refrigerator model ET8CHMXKB02, it has the ice maker in the freezer. I noticed a pool under the fridge on the floor. I have traced the water back to the inlet on the back of the unit. It is where the 1/4" plastic tubing goes into the freezer. It is a steady drip. I have tightened the metal fastener but it still leaks. Anyone have any suggestions?

I appreciate the help