Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
	at aun.a(SourceFile:416)
	at biv.e(SourceFile:59)
	at biv.<init>(SourceFile:45)
	at bil.o(SourceFile:46)
	at rx.o(SourceFile:719)
	at rx.<init>(SourceFile:127)
	at cxd.a(SourceFile:96)
	at cxd.d(SourceFile:131)
	at net.minecraft.server.MinecraftServer.run(SourceFile:502)
	at java.lang.Thread.run(Unknown Source)

[21:04:21] [Client thread/INFO]: Loaded 0 recipes
[21:04:21] [Client thread/INFO]: Loaded 0 advancements
[21:04:21] [Server thread/INFO]: Starting integrated minecraft server version 18w08a
[21:04:21] [Server thread/INFO]: Generating keypair
[21:04:21] [Server thread/INFO]: Found new data pack vanilla, loading it automatically
[21:04:21] [Server thread/INFO]: Reloading ResourceManager: Default
[21:04:22] [Server thread/INFO]: Loaded 517 recipes
[21:04:23] [Server thread/INFO]: Loaded 560 advancements
[21:04:23] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.NullPointerException: null
	at auh.a(SourceFile:409) ~[minecraft-18w08a-client.jar:?]
	at bip.e(SourceFile:59) ~[minecraft-18w08a-client.jar:?]
	at bip.<init>(SourceFile:45) ~[minecraft-18w08a-client.jar:?]
	at bif.o(SourceFile:46) ~[minecraft-18w08a-client.jar:?]
	at rx.o(SourceFile:719) ~[minecraft-18w08a-client.jar:?]
	at rx.<init>(SourceFile:127) ~[minecraft-18w08a-client.jar:?]
	at cwp.a(SourceFile:96) ~[minecraft-18w08a-client.jar:?]
	at cwp.d(SourceFile:131) ~[minecraft-18w08a-client.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:502) [minecraft-18w08a-client.jar:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_152]
[21:04:23] [Server thread/ERROR]: This crash report has been saved to: D:\MultiMC\instances\1.12.22\.minecraft\crash-reports\crash-2018-02-23_21.04.23-server.txt
[21:04:23] [Server thread/INFO]: Stopping server
[21:04:23] [Server thread/INFO]: Saving players
[21:04:23] [Server thread/INFO]: Saving worlds