Hello, yogendrak2@chetu.
When integrating Postman into QuickBooks Online, you may have skipped some steps. Let's make sure Postman is set up correctly. I can connect you with the best available help to ensure you get the help you need.
I'd recommend reaching out to our Intuit Developer's center. They can walk you through the process of the setup process. You can either log in or create a new account by visiting our Intuit Developer's website. From there, you can submit your questions. Following that, someone from the developer's team will respond to any questions or concerns you may have.
I'm also adding this article for your reference: Set up and test queries in Postman.
You can also learn more about QuickBooks Online processes by visiting this resource: Get started with QuickBooks Online.
If you need anything else in QuickBooks Online, please let me know. I'll be around to help you.
