21w39a server crashes

[iGreenDogs]

I wanted to start a fabric server with a proximity chat mod, but when initially starting it up, I get the following (this is directly from the command prompt)

   C:\Users\my_name\Desktop\munhunt> java -jar fabric-server-launch.jar
   Exception in thread "main" java.lang.RuntimeException: Failed to setup Fabric server environment!
           at net.fabricmc.loader.launch.server.FabricServerLauncher.main(FabricServerLauncher.java:58)
   Caused by: java.lang.RuntimeException: java.lang.RuntimeException: An exception occurred when launching the server!
           at net.fabricmc.loader.launch.server.FabricServerLauncher.setup(FabricServerLauncher.java:116)
           at net.fabricmc.loader.launch.server.FabricServerLauncher.main(FabricServerLauncher.java:56)
   Caused by: java.lang.RuntimeException: An exception occurred when launching the server!
           at net.fabricmc.loader.launch.server.FabricServerLauncher.launch(FabricServerLauncher.java:70)
           at net.fabricmc.loader.launch.server.FabricServerLauncher.setup(FabricServerLauncher.java:114)
           ... 1 more
   Caused by: java.lang.reflect.InvocationTargetException
           at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
           at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
           at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
           at java.base/java.lang.reflect.Method.invoke(Method.java:567)
           at net.fabricmc.loader.launch.server.FabricServerLauncher.launch(FabricServerLauncher.java:68)
           ... 2 more
   Caused by: java.lang.NoClassDefFoundError: org/apache/logging/log4j/LogManager
           at net.fabricmc.loader.launch.common.FabricLauncherBase.<clinit>(FabricLauncherBase.java:48)
           at net.fabricmc.loader.launch.knot.KnotServer.main(KnotServer.java:27)
           ... 7 more
   Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.LogManager
           at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:636)
           at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:182)
           at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
           at net.fabricmc.loader.launch.server.InjectingURLClassLoader.loadClass(InjectingURLClassLoader.java:57)
           at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
           ... 9 more

I have tried starting it on my ubuntu server too with the exact same command, and got the same error. I also tried using an older version of the fabric installer. How am I supposed to fix it?

[warjort]

Answered on the bug report you raised #1758