Failed to load class SparkDemo on spark-submit

Question

I am trying to create a simple Hello World program with Scala to run on on Apache Spark 3.1.1. However I am getting the following error on spark-submit

I am using the below command:

spark-submit --class SparkDemo --master local --executor-memory 800m /Users/souravhazra/Downloads/SparkDemo.jar

This is my Scala code:

object SparkDemo {
   def main(args: Array[String]): Unit = {    
       println("Hello World")
   }
}

This is my build.sbt

I am stuck in this issue over a couple of days. Please help. Thanks in advance.