Players can't join my server due to a technical error

Hello guys!

So recently I was gone for 2 weeks. When I got back, I got a weird error in my console every time a player tried to join. This was followed by the player being kicked for "Connection lost: Timed Out".

Error:

08.07 16:08:10 [Disconnect] User net.minecraft.util.com.mojang.authlib.GameProfile@7120d14[id=60259256-7051-3109-ab09-21ab16067bc9,name=MIke10221999,properties={},legacy=false] (/209.188.6.210:52778) has disconnected, reason: Internal server error 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:469) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.MinecraftServer.u(MinecraftServer.java:558) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.DedicatedServer.v(DedicatedServer.java:260) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.MinecraftServer.v(MinecraftServer.java:667) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.ServerConnection.c(SourceFile:134) [custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.NetworkManager.a(NetworkManager.java:160) ~[custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.LoginListener.a(LoginListener.java:42) ~[custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.LoginListener.c(LoginListener.java:68) ~[custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO at net.minecraft.server.v1_7_R3.PlayerList.attemptLogin(PlayerList.java:369) ~[custom.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks] 08.07 16:08:10 [Server] INFO java.lang.NullPointerException 08.07 16:08:10 [Server] WARN Failed to handle packet for /209.188.6.210:52778

Thanks for any help!