In the console it said:
[14:28:24 ERROR]: Encountered an unexpected exception java.lang.RuntimeException: java.util.zip.ZipException: incorrect header check at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOProvider.callStage1(ChunkIOProvider.java:30) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOProvider.callStage1(ChunkIOProvider.java:1) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:336) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.util.AsynchronousExecutor.getSkipQueue(AsynchronousExecutor.java:295) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOExecutor.syncChunkLoad(ChunkIOExecutor.java:16) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:137) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:120) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:116) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:374) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:338) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:272) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:545) [Spigot.jar:git-Spigot-65e8124-8bf06d6] at java.lang.Thread.run(Unknown Source) [?:1.8.0_121] Caused by: java.util.zip.ZipException: incorrect header check at java.util.zip.InflaterInputStream.read(Unknown Source) ~[?:1.8.0_121] at java.io.BufferedInputStream.fill(Unknown Source) ~[?:1.8.0_121] at java.io.BufferedInputStream.read(Unknown Source) ~[?:1.8.0_121] at java.io.DataInputStream.readByte(Unknown Source) ~[?:1.8.0_121] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:75) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:53) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:43) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.RegionFileCache.d(RegionFileCache.java:87) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkRegionLoader.loadChunk(ChunkRegionLoader.java:62) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOProvider.callStage1(ChunkIOProvider.java:21) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] ... 12 more [14:28:24 ERROR]: Cause of unexpected exception was java.util.zip.ZipException: incorrect header check at java.util.zip.InflaterInputStream.read(Unknown Source) ~[?:1.8.0_121] at java.io.BufferedInputStream.fill(Unknown Source) ~[?:1.8.0_121] at java.io.BufferedInputStream.read(Unknown Source) ~[?:1.8.0_121] at java.io.DataInputStream.readByte(Unknown Source) ~[?:1.8.0_121] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:75) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:53) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.NBTCompressedStreamTools.a(NBTCompressedStreamTools.java:43) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.RegionFileCache.d(RegionFileCache.java:87) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkRegionLoader.loadChunk(ChunkRegionLoader.java:62) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOProvider.callStage1(ChunkIOProvider.java:21) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOProvider.callStage1(ChunkIOProvider.java:1) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:336) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.util.AsynchronousExecutor.getSkipQueue(AsynchronousExecutor.java:295) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at org.bukkit.craftbukkit.v1_12_R1.chunkio.ChunkIOExecutor.syncChunkLoad(ChunkIOExecutor.java:16) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:137) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:120) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:116) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:374) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:338) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:272) ~[Spigot.jar:git-Spigot-65e8124-8bf06d6] at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:545) [Spigot.jar:git-Spigot-65e8124-8bf06d6] at java.lang.Thread.run(Unknown Source) [?:1.8.0_121]
Please help.