We've had 3 or 4 people in recent few days with the exact same issue. I'm surprised the university is offering a dial up service. p2p is against most school policies nowadays. And in the other cases, they could connect once, but then not connect again at all.

If port 6346 is open then it might be a program filter/blocker the isp is using. (Can you change your isp?)

After opening LW it's best to leave it some time to connect. If still not working, go to Tools>Options>Connections & untick connect on startup & press the Apply button. Then go to LW's menu File>Disconnect. Wait a minute. Then File>Connect. If this doesn't work, then close LW, then open. Leave it 10-15 mins, then go to File>Connect & leave it another 10-15 mins.