net.minecraftforge.fml.loading.EarlyLoadingException: Duplicate mods found
Check the mods folder for duplicate mods
If you are using Embeddium, remove Rubidium
To start a server with jvm arguments, create a text document and paste
java -Xmx4G -jar forge.jar
pause
Just make sure the server.jar name is matching with the file name
Then rename the text document to start.bat
Then you can start this server with this file
-Xmx4G allocates 4 GB RAM to the server