How to access ssrs reports in one server from another ASP.NET application server

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ASP.NET

SSRS

Dear Friends,
I am using VS 2013,SQL 2012 EXPRESS EDITION WITH ADVANCES SERVICES.
I am using SSRS reports.we have two servers.Application server contains published website files.Another server contains Database and SSRS reports.I couldn't access ssrs report from application.How to access it?

I have tried and i am getting error "The request failed with HTTP status 401: Unauthorized."

report viewer 

 rptViewer.ProcessingMode = ProcessingMode.Remote; 
rptViewer.ServerReport.ReportServerUrl = new Uri(ConfigurationManager.AppSettings.Get("ReportServerUrl")); 
   string strReportLayout = Convert.ToString(s1["strReportLayout"]);
            rptViewer.ServerReport.ReportPath = ConfigurationManager.AppSettings.Get("ReportServerProject") + "/"+strReportLayout; //Passing the Report Path   
           IReportServerCredentials irsc = new CustomReportCredentials("sqldbusername", "sqldbpwd", "serverIP");

What I have tried:

web config file

<authentication mode="Windows"/>
<identity impersonate="true" />
<add key="ReportServerUrl" value="http://202.66.132.185:80/ReportServer" />

<add key="ReportServerProject" value="/RPTSSRS"/>