[20:21:34] [Server thread/ERROR] [net.minecraft.server.MinecraftServer]: Encountered an unexpected exception
net.minecraft.util.ReportedException: Exception while ticking a block
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:906) ~[MinecraftServer.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:472) ~[nz.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:782) ~[MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:636) [MinecraftServer.class:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_241]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/world/World$3
at net.minecraft.world.World.func_190524_a(World.java:722) ~[amu.class:?]
at net.minecraft.world.World.func_175685_c(World.java:650) ~[amu.class:?]
at net.minecraft.world.World.func_175722_b(World.java:596) ~[amu.class:?]
at net.minecraft.world.World.markAndNotifyBlock(World.java:534) ~[amu.class:?]
at net.minecraft.world.World.func_180501_a(World.java:513) ~[amu.class:?]
at net.minecraft.block.BlockDynamicLiquid.func_176375_a(BlockDynamicLiquid.java:190) ~[aqe.class:?]
at net.minecraft.block.BlockDynamicLiquid.func_180650_b(BlockDynamicLiquid.java:167) ~[aqe.class:?]
at net.minecraft.world.WorldServer.func_72955_a(WorldServer.java:889) ~[oo.class:?]
at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:341) ~[oo.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:899) ~[MinecraftServer.class:?]
... 4 more
[20:21:34] [Server thread/ERROR] [net.minecraft.server.MinecraftServer]: This crash report has been saved to: D:\试验服务器\.\crash-reports\crash-2020-04-25_20.21.34-server.txt
[20:21:34] [Server thread/INFO] [net.minecraft.server.MinecraftServer]: Stopping server

把DynamicLiquid删掉试试，如果删掉后不会崩溃就是这个东西的问题，查看是不是不对应服务端版本

DynamicLiquid在哪的emm这个崩溃今天才遇到一次 第一次

D:\试验服务器\.\crash-reports\crash-2020-04-25_20.21.34-server.txt

上传这个文件