[Server thread/FATAL] [net.minecraft.server.MinecraftServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_232]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_232]
	at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_232]
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(SourceFile:13) ~[hv$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_232]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_232]
	at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
	... 5 more