Hello, I am pretty new to server hosting, but i have hosted few servers for my friends already. About a month ago, this error started showing whenever I start my forge serve with run.batr: 

[cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 8.0.9+86+master.3cf110c starting: java version 16.0.1 by Oracle Corporation
Exception in thread "main" java.lang.IllegalAccessError: class cpw.mods.modlauncher.SecureJarHandler (in unnamed module @0x568bf312) cannot access class sun.security.util.ManifestEntryVerifier (in module java.base) because module java.base does not export sun.security.util to unnamed module @0x568bf312
        at cpw.mods.modlauncher.SecureJarHandler.lambda$static$1(SecureJarHandler.java:41)
        at cpw.mods.modlauncher.api.LamdbaExceptionUtils.uncheck(LamdbaExceptionUtils.java:95)
        at cpw.mods.modlauncher.SecureJarHandler.<clinit>(SecureJarHandler.java:41)
        at cpw.mods.modlauncher.Launcher.lambda$new$6(Launcher.java:55)
        at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
        at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:52)
        at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:47)
        at cpw.mods.modlauncher.Environment.computePropertyIfAbsent(Environment.java:62)
        at cpw.mods.modlauncher.Launcher.<init>(Launcher.java:55)
        at cpw.mods.modlauncher.Launcher.main(Launcher.java:66)
        at net.minecraftforge.server.ServerMain$Runner.runLauncher(ServerMain.java:63)
        at net.minecraftforge.server.ServerMain$Runner.access$100(ServerMain.java:60)
        at net.minecraftforge.server.ServerMain.main(ServerMain.java:57)

 

I have tried to reinstall forge and java, but niether worked. It shows if i run standard forge server, but even if i start it from server modpack file. 

Thanks in advance, every help is appriciated. 

Can you please show me an example, I am not sure what do you mean.

 

Thank you so much, it worked for me.