possible error, I think I guessed it, gives me vampirism and werewolves as a reference.
The game crashes while playing on the LAN server when loading the new biome.
Mountain example when I discover the desert. For everything else it works.

thanks

[23:26:23] [Server thread/FATAL] [ne.mi.co.ForgeMod/]: Preparing crash report with UUID 95367ed3-435b-4b94-87c8-c75d1d170316
[23:26:23] [Server thread/ERROR] [minecraft/MinecraftServer]: Encountered an unexpected exception
net.minecraft.crash.ReportedException: Exception ticking world
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:855) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:787) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:78) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:642) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.server.MinecraftServer.lambda$startServer$0(MinecraftServer.java:232) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at java.lang.Thread.run(Unknown Source) [?:1.8.0_281] {}
Caused by: java.lang.NoSuchMethodError: de.teamlapen.vampirism.tileentity.TotemHelper.getTotemPosition(Ljava/util/Collection;)Lnet/minecraft/util/math/BlockPos;
at de.teamlapen.werewolves.entities.ModEntityEventHandler.onEntityJoinWorld(ModEntityEventHandler.java:68) ~[werewolves:1.0.0-alpha+20210217-2341] {re:classloading}
at net.minecraftforge.eventbus.ASMEventHandler_1002_ModEntityEventHandler_onEntityJoinWorld_EntityJoinWorldEvent.invoke(.dynamic) ~[?:?] {}
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
at net.minecraft.world.server.ServerWorld.func_217440_f(ServerWorld.java:829) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:abnormals_core.mixins.json:ServerWorldMixin,pl:mixin:APP:immersiveengineering.mixins.json:coremods.ServerWorldMixin,pl:mixin:APP:betterweather.mixins.json:server.MixinServerWorld,pl:mixin:A}
at net.minecraft.world.server.ChunkManager.lambda$null$25(ChunkManager.java:592) ~[?:?] {re:classloading,pl:accesstransformer:B}
at com.mojang.datafixers.util.Either.lambda$mapLeft$0(Either.java:162) ~[datafixerupper-4.0.26.jar:?] {re:classloading}
at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[datafixerupper-4.0.26.jar:?] {}
at com.mojang.datafixers.util.Either.mapLeft(Either.java:162) ~[datafixerupper-4.0.26.jar:?] {re:classloading}
at net.minecraft.world.server.ChunkManager.lambda$func_219200_b$26(ChunkManager.java:569) ~[?:?] {re:classloading,pl:accesstransformer:B}
at java.util.concurrent.CompletableFuture.uniApply(Unknown Source) ~[?:1.8.0_281] {}
at java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source) ~[?:1.8.0_281] {}
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_281] {}
at net.minecraft.world.chunk.ChunkTaskPriorityQueueSorter.func_219083_b(SourceFile:58) ~[?:?] {re:classloading}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.world.server.ServerChunkProvider$ChunkExecutor.func_213166_h(ServerChunkProvider.java:514) ~[?:?] {re:classloading}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.world.server.ServerChunkProvider$ChunkExecutor.func_213168_p(ServerChunkProvider.java:522) ~[?:?] {re:classloading}
at net.minecraft.world.server.ServerChunkProvider.func_217234_d(ServerChunkProvider.java:267) ~[?:?] {re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:722) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:711) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) ~[?:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:696) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:646) ~[?:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:A}
... 2 more

This is a bug in the werewolf addon.
I think its an duplicate of TeamLapen/Werewolves#33.
There should be a fixed version already

solved by installing the said mod. Thanks so much