Sagar, please make changes to your Jenkins-Zero-To-Hero/java-maven-sonar-argocd-helm-k8s/spring-boot-app/JenkinsFile

1. replace iam-veeramalla with you repo name (BroDevOps)
2. replace with your email and username. git config user.email "abhishek.xyz@gmail.com" git config user.name "Abhishek Veeramalla"
3. Make sure u are creating creditials in Jenkins as mentioned in blog.

Hope this solve your issue.

DOCKER_IMAGE = "abhishekf5/ultimate-cicd:${BUILD_NUMBER}"

for above line replace abhishekf5 with your dockeruser.