The fact that it's happening with other games means that it is definitely on your end. Things to check:
is your internet connected (obviously is in this case since you can post and read here)?
Are all Firewall, antivirus programs, or other software that could block internet connections working and configured correctly (please see documentation on these)? Note that you might have specific ports you need to open to play some games. I can never remember what these are for HnH and they can vary per game.
Are you playing from a location that might have further restrictions on internet activity such as a school, work, public location? There's little you can do here, though if it's a University access (for personal and not class use), you can usually get the IT department to open the blocked ports. Otherwise, you might have to go with a proxy to get through this. I can't really recommend any free proxies that are efficient enough for game/broadband use.