[00:54:54] [Server thread/FATAL] [minecraft/IntegratedServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_211]
	at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_211]
	at net.minecraft.util.Util.func_181617_a(Util.java:48) [h.class:?]
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:246) [chd.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
Caused by: java.lang.NullPointerException
	at net.minecraft.advancements.PlayerAdvancements.func_194220_a(PlayerAdvancements.java:360) ~[np.class:?]
	at net.minecraft.network.NetHandlerPlayServer.func_194027_a(NetHandlerPlayServer.java:447) ~[pa.class:?]
	at net.minecraft.network.play.client.CPacketSeenAdvancements.func_148833_a(SourceFile:50) ~[lu.class:?]
	at net.minecraft.network.play.client.CPacketSeenAdvancements.func_148833_a(SourceFile:11) ~[lu.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:20) ~[hv$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_211]
	at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_211]
	at net.minecraft.util.Util.func_181617_a(Util.java:47) ~[h.class:?]
	... 3 more
[00:54:55] [Server thread/FATAL] [minecraft/IntegratedServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_211]
	at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_211]
	at net.minecraft.util.Util.func_181617_a(Util.java:48) [h.class:?]
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:246) [chd.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]
Caused by: java.lang.NullPointerException
	at net.minecraft.advancements.PlayerAdvancements.func_194220_a(PlayerAdvancements.java:360) ~[np.class:?]
	at net.minecraft.network.NetHandlerPlayServer.func_194027_a(NetHandlerPlayServer.java:447) ~[pa.class:?]
	at net.minecraft.network.play.client.CPacketSeenAdvancements.func_148833_a(SourceFile:50) ~[lu.class:?]
	at net.minecraft.network.play.client.CPacketSeenAdvancements.func_148833_a(SourceFile:11) ~[lu.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:20) ~[hv$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_211]
	at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_211]
	at net.minecraft.util.Util.func_181617_a(Util.java:47) ~[h.class:?]
	... 3 more