asp.net - The request failed with HTTP status 401: Unauthorized -

i have asp.net website uses reportviewer control. i'm using sql server 2008 reporting. reporting services on machine on local network , asp.net web site on local system. has been working fine same machine when access reports on network works

http:\\exampledomainname\reportsserver 

but when want access reports local host, i.e http:\localhost\reports following error :

the request failed http status 401: unauthorized. 

any other assistance appreciated.

set impersonation web service in web.config. user must have permissions on reporting server:

<identity impersonate="true" />