Without any explanation after working 2 days it stops giving this error, so we have been able to verify it when generating a new map. What we are sure of is that it is a spigot / wet bug. because our plugins work perfectly and this error happens with or without plugins. so please! fix this problem once. We are not sure that the server is good because of this error that happens without any explanation after working well days!
More error information:[16:49:49] [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.server.v1_14_R1.ReportedException: Exception generating new chunk
 at net.minecraft.server.v1_14_R1.MinecraftServer.b(MinecraftServer.java:1070) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.DedicatedServer.b(DedicatedServer.java:396) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.MinecraftServer.a(MinecraftServer.java:959) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.MinecraftServer.run(MinecraftServer.java:804) [spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at java.lang.Thread.run(Thread.java:748) [?:1.8.0_212]
Caused by: java.lang.NullPointerException
 at net.minecraft.server.v1_14_R1.WorldGenStronghold.a(SourceFile:46) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkGenerator.createStructures(ChunkGenerator.java:144) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkStatus.d(SourceFile:52) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkStatus.a(SourceFile:217) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.PlayerChunkMap.lambda$24(PlayerChunkMap.java:482) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.PlayerChunkMap.lambda$22(PlayerChunkMap.java:480) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952) ~[?:1.8.0_212]
 at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926) ~[?:1.8.0_212]
 at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442) ~[?:1.8.0_212]
 at net.minecraft.server.v1_14_R1.ChunkTaskQueueSorter.b(SourceFile:57) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.e(SourceFile:83) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.a(SourceFile:123) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.run(SourceFile:91) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157) ~[?:1.8.0_212]
[16:49:49] [Server thread/ERROR]:  Cause of unexpected exception was
java.lang.NullPointerException: null
 at net.minecraft.server.v1_14_R1.WorldGenStronghold.a(SourceFile:46) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkGenerator.createStructures(ChunkGenerator.java:144) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkStatus.d(SourceFile:52) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ChunkStatus.a(SourceFile:217) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.PlayerChunkMap.lambda$24(PlayerChunkMap.java:482) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.PlayerChunkMap.lambda$22(PlayerChunkMap.java:480) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952) ~[?:1.8.0_212]
 at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926) ~[?:1.8.0_212]
 at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442) ~[?:1.8.0_212]
 at net.minecraft.server.v1_14_R1.ChunkTaskQueueSorter.b(SourceFile:57) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.e(SourceFile:83) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.a(SourceFile:123) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at net.minecraft.server.v1_14_R1.ThreadedMailbox.run(SourceFile:91) ~[spigot.jar:git-Spigot-5e4e7f3-5f88938]
 at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) ~[?:1.8.0_212]
 at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157) ~[?:1.8.0_212]
[16:49:49] [Server thread/ERROR]: This crash report has been saved to: C:\Users\cesium.ABF\Desktop\MinecraftSpigot\.\crash-reports\crash-2019-07-17_16.49.49-server.txt
[16:49:49] [Server thread/INFO]: Stopping server