Authentication error while exporting the SSRS reports to excel from a timer job.

Question

Below code written in the timer job Execute() method to render the reports and get the byte array but it works fine when the application run in windows authentication, but throw error when the application extended to Form based authentication in SharePoint
2013. 
The sample code is:
Microsoft.Reporting.WebForms.ReportViewer rview = new Microsoft.Reporting.WebForms.ReportViewer();
rview.ServerReport.ReportServerUrl = new Uri(reportLib.ParentWeb.Site.RootWeb.Url + "/_vti_bin/ReportServer");
                                        System.Collections.Generic.List<Microsoft.Reporting.WebForms.ReportParameter> paramList = new System.Collections.Generic.List<Microsoft.Reporting.WebForms.ReportParameter>();
                                        rview.ServerReport.ReportPath = reportLib.ParentWeb.Url + RAConstants.LibraryReportLibraryUrl + repotName;
                                        string mimeType, encoding, extension, deviceInfo;
                                        string[] streamids;
                                        Microsoft.Reporting.WebForms.Warning[] warnings;
                                        string format = "Excel";
deviceInfo =
                                        "<DeviceInfo>" +
                                        "<SimplePageHeaders>True</SimplePageHeaders>" +
                                        "</DeviceInfo>";
bytes = rview.ServerReport.Render(format, deviceInfo, out mimeType, out encoding, out extension, out streamids, out warnings);
In above Render() i got below error exception. 
ex.ToString() "Microsoft.Reporting.WebForms.ReportServerException: Report Server has encountered a SharePoint error. (rsSharePointError) ---> Microsoft.Reporting.WebForms.ReportServerException: The user does not exist or is not unique. ---> Microsoft.Reporting.WebForms.ReportServerException:
The user does not exist or is not unique.\r\n   --- End of inner exception stack trace ---\r\n   --- End of inner exception stack trace ---\r\n   at Microsoft.Reporting.WebForms.SoapReportExecutionService.ServerReportSoapProxy.OnSoapException(SoapException
e)\r\n   at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.ProxyMethodInvocation.Execute[TReturn](RSExecutionConnection connection, ProxyMethod`1 initialMethod, ProxyMethod`1 retryMethod)\r\n   at
Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.LoadReport(String Report, String HistoryID)\r\n   at Microsoft.Reporting.WebForms.SoapReportExecutionService.LoadReport(String report, String historyId)\r\n
  at Microsoft.Reporting.WebForms.ServerReport.EnsureExecutionSession()\r\n   at Microsoft.Reporting.WebForms.ServerReport.Render(String format, String deviceInfo, PageCountMode pageCountMode, String& mimeType, String& encoding, String&
fileNameExtension, String[]& streams, Warning[]& warnings)\r\n   at Microsoft.Reporting.WebForms.Report.Render(String format, String deviceInfo, String& mimeType, String& encoding, String& fileNameExtension, String[]& streams,
Warning[]& warnings)\r\n   at ResourceAllocationUI.SPJobs.SendWeeklyReportInEmail.Execute(Guid contentDbId)" string
Please help. Thanks in advance.
Thanks,
Rashmi Ranjan

Answer 1

Likely because your user is continuing to call the service in a Windows (classic) DOMAIN\username format, and not in the Claims identity it should be.
Trevor Seward
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