New Development- MC Server Not Working.

I've been running a Mine Craft Server now for a few years, so I usually know how to fix any issues that come up on my own.
I recently tried starting up MC Sever 14w11b, the version my friends and myself had been playing on for a while. Though none of us had changed anything, an all of our Hamachis were working just fine, and I could connect to my sever and the server did not show any problems, none of my friends could not connect to the server, though we all checked to make sure we were all running the same version.

So I upgraded my Snapshot of the game to 14w21b, and Server, and so did my friends, and I can get on just fine, sever shows no issues, but my friends still can not connect.
I've run through all of the trouble shooting I know how to do and I'm out of answers.