Hi @aakash.gupta, sorry to hear you’re having some difficulties. Can you please check out these guidelines on how to ask questions here on the forum? If you can provide a little more context, if might make it easier to provide more insight.
But my initial guess is that it’s an issue with Jenkins and npm playing together, not necessarily Postman. Here’s an issue on Stack Overflow where other users had issues with Jenkins not being able to find npm.