Hi Arunkumar,
can you check that the document has sales organization assigned. The user needs to be assigned to the same sales organization via the position.
When you test the authorization and search for business transactions please consider that authorization values are buffered and not active immediately. You could deactivate this buffer for the time of your testing. You can see KBA 1888432 for more information.
(http://service.sap.com/sap/support/notes/1888432)
Best regards
Marion