It's because the network's DNS is blocking the p2p protocol. Open up your Network and Sharing, click on whichever adapater you're trying to connect with (either Ethernet or maybe WiFi), then click on Properties, Double-Click on IPv4, then use your own DNS and enter 8.8.8.8 as the primary and 8.8.4.4 as the secondary. Those are Google's DNS servers. That's how I get away with torrenting at the library lol.
Some places, this doesn't work. I've yet to know why though, but for the most part it works.