A question on non-Hamachi multiplayer

My cousin and I have been playing multiplayer with no problems for the past couple of days, but all of a sudden he cannot connect to my server. We have been using my personal IP address and the 7777 port with no problems until yesterday.

Is there anything that doesn't involve 3rd party software that we can do? (My internet is not a fan of Hamachi)

*edit: He says it is getting stuck on the "connecting" screen