macskaúr

You were right. It was Optifine. I disabled it and everyting worked. Thank you so much!

Does Optifine not work on 1.16.4? I had installed that version too and it gave the same error.

Here is the log. 08.12 12:25:29 [Multicraft] Starting server! 08.12 12:25:29 [Multicraft] Loaded config for "Custom JAR (Place "custom.jar" in base directory)" 08.12 12:25:31 [Multicraft] Updating eula.txt file 08.12 12:25:31 [Server] INFO WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. 08.12 12:25:33 [Server] INFO 2021-12-08 12:25:33,132 main WARN Advanced terminal features are not available in this environment 08.12 12:25:33 [Server] main/INFO [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher running: args [--gameDir, ., --launchTarget, fmlserver, --fml.forgeVersion, 35.1.37, --fml.mcpVersion, 20201102.104115, --fml.mcVersion, 1.16.4, --fml.forgeGroup, net.minecraftforge, nogui] 08.12 12:25:33 [Server] main/INFO [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 8.0.9+86+master.3cf110c starting: java version 1.8.0_275 by Oracle Corporation 08.12 12:25:33 [Server] main/INFO [op.OptiFineTransformationService/]: OptiFineTransformationService.onLoad 08.12 12:25:33 [Server] main/INFO [op.OptiFineTransformationService/]: OptiFine ZIP file: /mods/OptiFine-1.16.4_HD_U_G7.jar 08.12 12:25:33 [Server] main/INFO [op.OptiFineTransformer/]: Target.PRE_CLASS is available 08.12 12:25:33 [Server] main/INFO [ne.mi.fm.lo.FixSSL/CORE]: Added Lets Encrypt root certificates as additional trust 08.12 12:25:33 [Server] main/INFO [mixin/]: SpongePowered MIXIN Subsystem Version=0.8.2 Source=file:/libraries/org/spongepowered/mixin/0.8.2/mixin-0.8.2.jar Service=ModLauncher Env=SERVER 08.12 12:25:33 [Server] main/INFO [op.OptiFineTransformationService/]: OptiFineTransformationService.initialize 08.12 12:25:34 [Server] main/INFO [op.OptiFineTransformationService/]: OptiFineTransformationService.transformers 08.12 12:25:34 [Server] main/INFO [op.OptiFineTransformer/]: Targets: 308 08.12 12:25:35 [Server] main/INFO [op.OptiFineTransformationService/]: additionalClassesLocator: [optifine., net.optifine.] 08.12 12:25:35 [Server] main/INFO [mixin/]: Successfully loaded Mixin Connector [vazkii.botania.common.MixinConnector] 08.12 12:25:35 [Server] main/INFO [mixin/]: Successfully loaded Mixin Connector [vazkii.patchouli.common.MixinConnector] 08.12 12:25:35 [Server] main/INFO [cp.mo.mo.LaunchServiceHandler/MODLAUNCHER]: Launching target 'fmlserver' with arguments [--gameDir, ., nogui] 08.12 12:25:36 [Server] main/FATAL [ne.mi.fm.lo.RuntimeDistCleaner/DISTXFORM]: Attempted to load class net/minecraft/client/gui/screen/Screen for invalid dist DEDICATED_SERVER 08.12 12:25:36 [Server] INFO Exception in thread "main" [12:25:36] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: java.lang.RuntimeException: java.lang.reflect.InvocationTargetException 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:39) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.Launcher.run(Launcher.java:82) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.Launcher.main(Launcher.java:66) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraftforge.server.ServerMain$Runner.runLauncher(ServerMain.java:63) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraftforge.server.ServerMain$Runner.access$100(ServerMain.java:60) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraftforge.server.ServerMain.main(ServerMain.java:57) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: Caused by: java.lang.reflect.InvocationTargetException 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at java.lang.reflect.Method.invoke(Method.java:498) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at net.minecraftforge.fml.loading.FMLServerLaunchProvider.lambda$launchService$0(FMLServerLaunchProvider.java:51) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1061]: ... 7 more 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: Caused by: java.lang.ExceptionInInitializerError 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: at net.minecraft.crash.CrashReport.func_71504_g(CrashReport.java:101) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: at net.minecraft.crash.CrashReport.<init>(CrashReport.java:54) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: at net.minecraft.crash.CrashReport.func_230188_h_(CrashReport.java:425) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: at net.minecraft.server.Main.main(Main.java:91) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:644]: ... 13 more 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: Caused by: java.lang.RuntimeException: Attempted to load class net/minecraft/client/gui/screen/Screen for invalid dist DEDICATED_SERVER 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at net.minecraftforge.fml.loading.RuntimeDistCleaner.processClassWithFlags(RuntimeDistCleaner.java:71) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:265) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at java.lang.ClassLoader.loadClass(ClassLoader.java:351) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: at net.optifine.reflect.Reflector.<clinit>(Reflector.java:184) 08.12 12:25:36 [Server] main/INFO [STDERR/]: [java.lang.Throwable:printStackTrace:668]: ... 17 more 08.12 12:25:37 [Multicraft] Server shut down (starting) 08.12 12:25:37 [Multicraft] Restarting crashed server in 10 seconds 08.12 12:25:37 [Multicraft] Looks like a crash, check the server console. Return value: 1 08.12 12:25:37 [Multicraft] Server stopped 08.12 12:25:40 [Multicraft] Received stop command 08.12 12:25:40 [Multicraft] Server stopped The server works without mods, but not with them. Forge is installed on the server.