Thanks Phani, so it is all about authorization and roles. I got my answer. 
Just one thing here, as we do not have any portal team to publish the report so how can I publish Bex query in portal directly. I tried to use from menu button in Bex query designer but could not do it means nothing happen if I hit the 'Publish to Portal'.
Please share any document if you know.
Regards
Ansh
Message was edited by: Ansh Kaushik