Why can't I connect to my friend's hamachi minecraft server?

Hey everyone, I have hamachi, and so does my friend who is the host of the server. I have been connecting to his server for the psat month now on minecraft, but today, it just said " Failed to connect to server, Connection timed out: connect". I can connect to other servers fine, just not his one. Also, Our other friends cant connect to this server either. What is the problem? Is it that Hamachi has too many people trying to connect to servers that it just doesn't connect me, or is it something with the settings of the server? Or is it my friend's internet connection? Thanks.