I have spent hours troubleshooting this issue. There are numerous posts about 401.1 errors using SSRS in integrated mode with SharePoint however none of them address an intermittent issue like ours. Intermittently when running reports from our SharePoint reports centre we will receive an error: "The request failed with HTTP status 401: Unauthorizied" We can refresh the page anywhere from 1 to several times and then it might run. It seems to be worse when lots of reports are being run. The SharePoint and Reporting Services servers do not appear to undergo a performance decrease during times when we are receiving this error however. The setup is as follows: Server 1: SharePoint 2010 on Windows Server 2k8 Standard R2 (single WFE and app server) Server 2: SQL 2k8 R2 Reporting Services installed in integrated mode. SharePoint 2010 installed. Windows Server 2k8 Standard with SP2 Server 3: SQL 2k8 R2 (SharePoint databases). Using a SQL alias. We are using Kerberos and have SPNs set up for the SQL service account, the reporting services service account and the SharePoint application pool service account. No network load balancing. The following errors are reported on the SharePoint server: 03/08/2012 14:03:54.64 w3wp.exe (0x1600) 0x1990 SQL Server Reporting Services UI Pages aacy High Web part failed in OnPreRender: System.Net.WebException: The request failed with HTTP status 401: Unauthorized. at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.GetSecureMethods() at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.IsSecureMethod(String methodname) at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.SetConnectionSSLForMethod(String methodname) at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.ProxyMethodInvocation.Execute[TReturn](RSExecutionConnection connection, ProxyMethod`1 initialMethod, ProxyMethod`1 retryMethod) at Microsoft.Reporting.WebForms.ServerRep... 7201dbd9-db69-4426-94f2-2fd29ed83bfd 03/08/2012 14:03:54.64* w3wp.exe (0x1600) 0x1990 SQL Server Reporting Services UI Pages aacy High ...ort.EnsureExecutionSession() at Microsoft.Reporting.WebForms.ServerReport.GetParameters() at Microsoft.ReportingServices.SharePoint.UI.WebParts.ReportViewerWebPart.GetFilterValues(FilterParametersCollection& filterValues, ReportParameter[]& noLongerSpecifiedFilters) at Microsoft.ReportingServices.SharePoint.UI.WebParts.ReportViewerWebPart.HandleParameters() at Microsoft.ReportingServices.SharePoint.UI.WebParts.ReportViewerWebPart.OnPreRender(EventArgs e) 7201dbd9-db69-4426-94f2-2fd29ed83bfd Have also seen this error, but it does not seem to come up every time: Exception encountered for SOAP method GetSystemProperties: System.Net.WebException: The request failed with HTTP status 401: Unauthorized. at Microsoft.SqlServer.ReportingServices2010.RSConnection2010.SetConnectionProtocol() I have looked through the report server service trace log and it does not appear that the request ever reaches the reporting services server.

To address each of your suggestions: "To change the Reporting Services Web service virtual directory to use Windows Authentication, follow these steps:" Both ASP.Net Impersonation and Windows Authentication are enabled. All other options are disabled. Do we need to disable ASP.Net Impersonation as well? Every SharePoint web application seems to have these settings by default "Configure Reporting Services Integration to use Trusted Account instead of Windows Integrated. Follow these steps to change this setting:" We have a requirement to use Kerberos authentication, so changing it to use Trusted Account is not an option for us. Note that Kerberos does work most of the time, but we intermittently get the 401 errors. "Configure Kerberos authentication, and then configure SharePoint to correctly use Kerberos authentication." Kerberos has been configured for SharePoint and there is absolutely no issue with users accessing SharePoint using Kerberos authentication. And again, reports work using Kerberos authentication most of the time. If there was something inherently wrong with the setup I would imagine that it would fail all of the time, not just intermittently. We followed the documentation on how to configure Kerberos and got it all working with no hassles, other than our intermittent report access issues we are now trying to resolve. The authentication provider on the SharePoint web application is set to negotiate. "Edit the DisableLoopbackCheck registry key using the steps in section 10.1, "How to Change the DisableLoopbackCheck Registry Key." The diableloopbackcheck registry is set on the SharePoint server (although this isn't best practice but was done as part of my troubleshooting - we will change it to use backconnectionhostnames instead). Disableloopbackcheck is not set on the reporting services server however - it was my understanding that this is not required because the report server is not using a host header (the report server URL set up is http://servername/ReportServer). Please correct me if I am wrong. "To verify that integrated Windows authentication is enabled, follow these steps:" Enable Integrated Windows Authentication is selected.

Kylie, i'm having a similar problem with intermittent errors. however, i typically can get the report to run by clicking the refresh icon in the SSRS toolbar. Have you had any sucess getting this resolved? TIA DeanDean MCTS-SQL 2005 Business Intelligence, SharePoint 2010, Configuration

Dean, Did you get any solution to this. I have the exact same issue as Kylie and yourself Thanks Fergal

ok lets us know how you get on if you find a solution. Will do likewise