what bug? I need support
[23:13:04] [Head Conversion Thread - 0/WARN]: Couldn't look up profile properties for com.mojang.authlib.GameProfile@53580f[id=606e2ff0-ed77-4842-9d6c-e1d3321c7838,name=MHF_Question,properties={},legacy=false]
com.mojang.authlib.exceptions.AuthenticationUnavailableException: Cannot contact authentication server
at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:85) ~[spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService.fillGameProfile(YggdrasilMinecraftSessionService.java:180) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService.fillProfileProperties(YggdrasilMinecraftSessionService.java:173) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at net.minecraft.server.v1_11_R1.TileEntitySkull$1.load(TileEntitySkull.java:76) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at net.minecraft.server.v1_11_R1.TileEntitySkull$1.load(TileEntitySkull.java:1) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache.get(LocalCache.java:3934) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4827) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at net.minecraft.server.v1_11_R1.TileEntitySkull$3.run(TileEntitySkull.java:201) [spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_141]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_141]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_141]
Caused by: java.io.IOException: Server returned HTTP response code: 503 for URL:
https://sessionserver.mojang.com/session/minecraft/profile/606e2ff0ed7748429d6ce1d3321c7838?unsigned=false
at sun.net.
www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source) ~[?:1.8.0_141]
at sun.net.
www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) ~[?:1.8.0_141]
at sun.net.
www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source) ~[?:1.8.0_141]
at com.mojang.authlib.HttpAuthenticationService.performGetRequest(HttpAuthenticationService.java:130) ~[spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:66) ~[spigot-1.11.2.jar:git-Spigot-3fb9445-6e3cec8]
... 16 more