[13:35:19] [Server thread/WARN]: java.util.zip.ZipException: Not in GZIP format
[13:35:19] [Server thread/WARN]:         at java.util.zip.GZIPInputStream.readHeader(Unknown Source)
[13:35:19] [Server thread/WARN]:         at java.util.zip.GZIPInputStream.<init>(Unknown Source)
[13:35:19] [Server thread/WARN]:         at java.util.zip.GZIPInputStream.<init>(Unknown Source)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:18)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.PersistentCollection.get(PersistentCollection.java:50)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.WorldServer.b(WorldServer.java:79)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.SecondaryWorldServer.b(SecondaryWorldServer.java:63)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:325)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:292)
[13:35:19] [Server thread/WARN]:         at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:616)
[13:35:19] [Server thread/WARN]:         at java.lang.Thread.run(Unknown Source)