issue

15.06 14:25:02 [Server] ERROR Current Thread: Keep-Alive-Timer
15.06 14:25:02 [Server] ERROR ------------------------------
15.06 14:25:02 [Server] ERROR Entire Thread Dump:
15.06 14:25:02 [Server] ERROR ------------------------------
15.06 14:25:02 [Server] ERROR java.lang.Thread.run(Unknown Source)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:726)
15.06 14:25:02 [Server] ERROR org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350)
15.06 14:25:02 [Server] ERROR org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71)
15.06 14:25:02 [Server] ERROR com.gmail.nossr50.runnables.player.PowerLevelUpdatingTask.run(PowerLevelUpdatingTask.java:10)
15.06 14:25:02 [Server] ERROR com.gmail.nossr50.util.scoreboards.ScoreboardManager.<clinit>(ScoreboardManager.java:110)
15.06 14:25:02 [Server] ERROR com.gmail.nossr50.util.scoreboards.ScoreboardManager.getOfflinePlayerDots(ScoreboardManager.java:125)
15.06 14:25:02 [Server] ERROR com.gmail.nossr50.util.scoreboards.ScoreboardManager.getOfflinePlayer(ScoreboardManager.java:133)
15.06 14:25:02 [Server] ERROR org.bukkit.craftbukkit.v1_8_R3.CraftServer.getOfflinePlayer(CraftServer.java:1300)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.UserCache.getProfile(UserCache.java:145)
15.06 14:25:02 [Server] ERROR net.minecraft.server.v1_8_R3.UserCache.a(UserCache.java:85)
15.06 14:25:02 [Server] ERROR com.mojang.authlib.yggdrasil.YggdrasilGameProfileRepository.findProfilesByNames(YggdrasilGameProfileRepository.java:81)
15.06 14:25:02 [Server] ERROR java.lang.Thread.sleep(Native Method)
15.06 14:25:02 [Server] ERROR Stack:
15.06 14:25:02 [Server] ERROR PID: 14 | Suspended: false | Native: false | State: TIMED_WAITING
15.06 14:25:02 [Server] ERROR Current Thread: Server thread
15.06 14:25:02 [Server] ERROR ------------------------------
15.06 14:25:01 [Server] ERROR Server thread dump (Look for plugins here before reporting to Spigot!):
15.06 14:25:01 [Server] ERROR ------------------------------
15.06 14:25:01 [Server] ERROR Spigot version: git-Spigot-044d928-e8c6403 (MC: 1.8.6)
15.06 14:25:01 [Server] ERROR Be sure to include ALL relevant console errors and Minecraft crash reports
15.06 14:25:01 [Server] ERROR Please report this to http://www.spigotmc.org/
15.06 14:25:01 [Server] ERROR The server has stopped responding!