That probably means there's an external firewall you have no control over that goes to the school or residence before it gets to you. Try changing the listening port in LW to 64049. ie: go to LW's menu bar, Tools>Options>Advanced>Firewalls & change the listening port there. Then press apply. Perhaps disconnect & reconnect from the file menu.

Unfortunately there may be no easy answer when it comes connecting thru a school or school residence.