[16:42:45] [Server thread/INFO]: [XieSimpleGuilds] [INFO] Loaded 20 player commands.
[16:42:45] [Head Conversion Thread - 0/WARN]: Couldn't look up profile properties for com.mojang.authlib.GameProfile@23825077[id=51137b33-aa8d-4009-8e39-f495a4544e46,name=NacOJerk,properties={},legacy=false]
com.mojang.authlib.exceptions.AuthenticationUnavailableException: Cannot contact authentication server
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:85) ~[spigot.jar:git-Paper-1094]
	at com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService.fillGameProfile(YggdrasilMinecraftSessionService.java:180) [spigot.jar:git-Paper-1094]
	at com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService.fillProfileProperties(YggdrasilMinecraftSessionService.java:173) [spigot.jar:git-Paper-1094]
	at net.minecraft.server.v1_11_R1.TileEntitySkull$1.load(TileEntitySkull.java:76) [spigot.jar:git-Paper-1094]
	at net.minecraft.server.v1_11_R1.TileEntitySkull$1.load(TileEntitySkull.java:43) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache.get(LocalCache.java:3934) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) [spigot.jar:git-Paper-1094]
	at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4827) [spigot.jar:git-Paper-1094]
	at net.minecraft.server.v1_11_R1.TileEntitySkull$3.run(TileEntitySkull.java:201) [spigot.jar:git-Paper-1094]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_131]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_131]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_131]
Caused by: java.io.IOException: Server returned HTTP response code: 503 for URL: https://sessionserver.mojang.com/session/minecraft/profile/51137b33aa8d40098e39f495a4544e46?unsigned=false
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1876) ~[?:1.8.0_131]
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474) ~[?:1.8.0_131]
	at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254) ~[?:1.8.0_131]
	at com.mojang.authlib.HttpAuthenticationService.performGetRequest(HttpAuthenticationService.java:130) ~[spigot.jar:git-Paper-1094]
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:66) ~[spigot.jar:git-Paper-1094]
	... 16 more