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.
