Hey so I don't know what I'm doing wrong here 

The startup code I'm using:

Spoiler

java -Xmx4096M -Xms1024M -jar forge-1.16.5-36.2.4.jar nogui
PAUSE

 

and here is what happens in the Console:

Spoiler

C:\Users\yassi\Desktop\Omran 2.0 Server>java -Xmx4096M -Xms1024M -jar forge-1.16.5-36.2.4.jar nogui
2021-09-19 18:56:38,378 main WARN Advanced terminal features are not available in this environment
[18:56:38] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher running: args [--gameDir, ., --launchTarget, fmlserver, --fml.forgeVersion, 36.2.4, --fml.mcpVersion, 20210115.111550, --fml.mcVersion, 1.16.5, --fml.forgeGroup, net.minecraftforge, nogui]
[18:56:38] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 8.0.9+86+master.3cf110c starting: java version 16.0.2 by Oracle Corporation
Exception in thread "main" java.lang.IllegalAccessError: class cpw.mods.modlauncher.SecureJarHandler (in unnamed module @0x589b3632) cannot access class sun.security.util.ManifestEntryVerifier (in module java.base) because module java.base does not export sun.security.util to unnamed module @0x589b3632
        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)

C:\Users\yassi\Desktop\Omran 2.0 Server>PAUSE
Press any key to continue . . .

 

 

What java version are you using (run "java -version" to get it)

22 minutes ago, ImNotJahan said:

What java version are you using (run "java -version" to get it)

It says it in the log. It's 16.

36 minutes ago, Yassaaa said:

Hey so I don't know what I'm doing wrong here

You need to use Java 8 instead of Java 16 for versions before 1.17.