Hi @gouri.ghode,
You’re welcome.
It seems like you may have not set the variable in the Postman Environment you’re using. I am not exactly sure how you are getting into this issue, but I just made a video that might be helpful.
If you still have an issue, can you show me a screenshot of your setup? Including your Pre-request script, GraphQL query, and Postman Environment? That should clear things up for me to provide the best advice.
I hope this helps!