MC Error

java.lang.Error
	at sun.misc.Unsafe.park(Native Method)
	at java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
	at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.bl(SourceFile:139)
	at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.awaitTasks(SourceFile:129)
	at net.minecraft.server.v1_15_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:107)
	at net.minecraft.server.v1_15_R1.World.getChunkAt(World.java:186)
	at net.minecraft.server.v1_15_R1.IWorldReader.getChunkAt(SourceFile:108)
	at net.minecraft.server.v1_15_R1.World.getChunkAt(World.java:181)
	at net.minecraft.server.v1_15_R1.World.getType(World.java:495)
	at net.minecraft.server.v1_15_R1.VoxelShapes.a(SourceFile:259)
	at net.minecraft.server.v1_15_R1.VoxelShapes.a(SourceFile:207)
	at net.minecraft.server.v1_15_R1.Entity.a(Entity.java:816)
	at net.minecraft.server.v1_15_R1.Entity.a(Entity.java:771)
	at net.minecraft.server.v1_15_R1.Entity.e(Entity.java:739)
	at net.minecraft.server.v1_15_R1.Entity.move(Entity.java:512)
	at net.minecraft.server.v1_15_R1.EntityLiving.e(EntityLiving.java:2177)
	at net.minecraft.server.v1_15_R1.EntityPig.e(EntityPig.java:223)
	at net.minecraft.server.v1_15_R1.EntityLiving.movementTick(EntityLiving.java:2532)
	at net.minecraft.server.v1_15_R1.EntityInsentient.movementTick(EntityInsentient.java:504)
	at net.minecraft.server.v1_15_R1.EntityAgeable.movementTick(EntityAgeable.java:145)
	at net.minecraft.server.v1_15_R1.EntityAnimal.movementTick(EntityAnimal.java:28)
	at net.minecraft.server.v1_15_R1.EntityLiving.tick(EntityLiving.java:2341)
	at net.minecraft.server.v1_15_R1.EntityInsentient.tick(EntityInsentient.java:273)
	at net.minecraft.server.v1_15_R1.WorldServer.entityJoinedWorld(WorldServer.java:607)
	at net.minecraft.server.v1_15_R1.WorldServer$$Lambda$2886/8095365.accept(Unknown Source)
	at net.minecraft.server.v1_15_R1.World.a(World.java:669)
	at net.minecraft.server.v1_15_R1.WorldServer.doTick(WorldServer.java:387)
	at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1023)
	at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:386)
	at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:940)
	at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:789)
	at java.lang.Thread.run(Unknown Source)