*I am aware that this question has already been answered in the comments. I'm writing this so this question will be removed from the list of unanswered questions.*

It seem that you use a cracked Minecraft launcher which means that your account can not be verified on the Mojang servers. A way around this is to go to `server.properties` and change online mode to `false` this will allow you to connect to your server without the server verifying the legitimacy of your account

**Original answer by [Dillmo](http://gaming.stackexchange.com/users/52890/dillmo).**