That suggests your router is the issue. But before we move onto that. (After all, LW worked for you before!) Let's try some different ports for LW to use. Go to LW's menu bar, Tools>Options>Advanced>Firewalls & change the listening port to something else & press the apply button. Here's some other ports you can try: 1111, 3500, 4008, 1203, 80, 20282, 10000, 443, 40475.

After changing the port, you can do a port test here (but LW must be open at the same time!!!): http://home.no.net/tgrumpy/ct/dex.php & type in the port no. you changed LW to listen to.