Having Troubles with my 1.6.4 Server

So my MineCraft server has been having issues lately. A few days ago I tried to join my server and it said

I DO have a Premium account, I play on Premium only servers all the time including mine. All of a sudden most of my friends cant join either for the same problem. It is getting annoying, sometimes we can join but most of the time we can't.

Anyways I am looking for a solution to the

Please help me out, will be greatly appreciated.

Extra Information:
This server is running CraftBukkit version git-Spigot-1137 (MC: 1.6.4) (Implementing API version 1.6.4-R2.1-SNAPSHOT)

This is the Error Message:

 

I am getting the same thing...

I tried to logout of my mc account then relog and wont work, then i reloaded my server since it sometimes works for me, but still same problem

 

This is happening with a lot of people lately. It's a problem on Mojang's end, not yours. You'll just have to wait it out. Here's a website to check and see how the Mojang stuff is working: http://xpaw.ru/mcstatus/

 

Locked. We don't support Spigot.