SSRS in SharePoint integration mode gets HTTP status 401: Unauthorized error on only one server

My environment has two web front ends for SharePoint. We have SSRS (SQL Server Reporting Services) installed on one of them. I have used Central Administration to integrate the two. If I access a SSRS report using a load balanced url, about 50% of the time I get the following error (in the SharePoint logs).


Exception encountered for SOAP method GetSystemProperties: System.Net.WebException: The request failed with HTTP status 401: Unauthorized.     at Microsoft.SqlServer.ReportingServices2010.RSConnection2010.SetConnectionProtocol()     at Microsoft.SqlServer.ReportingServices2010.RSConnection2010.SoapMethodWrapper`1.ExecuteMethod(Boolean setConnectionProtocol)

System.Net.WebException: The request failed with HTTP status 401: Unauthorized.    at Microsoft.ReportingServices.SharePoint.UI.RSConnectionInfo.get_SPManagementProxy()     at Microsoft.ReportingServices.SharePoint.UI.RSItemPickerNavigator.ListParents(String item)     at Microsoft.ReportingServices.SharePoint.UI.RSItemPickerNavigator.GetParentItemUrl(String enumerableLocation)     at Microsoft.ReportingServices.SharePoint.UI.ItemSelectorDialogControl.ValidatePath(String unvalidatedPath, Boolean useFallbackPath, String& itemPathParent, String& itemPathGrandparent, String& invalidReason)     at Microsoft.ReportingServices.SharePoint.UI.ItemSelectorDialogControl.OnPreRender(EventArgs e)     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Control.PreRenderRecursiveInternal()     at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

If I use a url that goes directly to one of the servers, I soon see that predictably I get the error for only one of the servers. How weird. I also found that if I add the Reporting Services web part to a page and then try to select a report I get the same error. The good thing is that I then got a correlation id which I could then use to find the exact error in the SharePoint logs.

So I verified a bunch of things:

• Changed Reporting Services to be a single server deployment instead of a scaled out deployment (just to make things easier to troubleshoot).
• The patch level is the same for the servers
• The files are identical on both servers
• Tried using the IP address of the reporting server instead of the host name in Central Admin | Reporting Services Integration | Report Server Web Service URL.
• Changing logging in Reporting Services to verbose. Click here for instructions.
• Disable loopback check. Click here for instructions and security risks.
• Selected Authentication Mode to Trusted Account in Central Admin | Reporting Services Integration | Authentication Mode. I was using a service account before that.

I believe the last thing I tried was the key change that solved it, but the other items could also have helped (though it never worked until I made the last change).

Lots of docs I read through to try to figure out what was wrong. If the above doesn't work, you may want to start with one of the links below.

• The one stop shop for FIXING your Reporting Service's Issues
• Configuring Reporting Services for SharePoint 2010 Integration
• Server Deployment Checklist
• How Do I learn About SharePoint Integrated Mode
• Storing and Synchronizing Report Server Content With SharePoint Databases
• Troubleshooting Configuration Problems
• Security Overview for Reporting Services in SharePoint Integrated Mode
• How to: Install and Configure SharePoint Integration on Multiple Servers
• Deployment Topologies for Reporting Services in SharePoint Integrated Mode
• Granting Permissions on Report Server Items on a SharePoint Site
• How to: Set Permissions for Report Server Items on a SharePoint Site (Reporting Services in SharePoint Integrated Mode)
• How to: Configure a Report Server on a Network Load Balancing Cluster
• Reporting Services Log Files
• Reporting Services SharePoint Integration Troubleshooting
• How to: Configure Report Server Integration in SharePoint Central Administration
• Configuring the Report Server Service Account
• Integrating SharePoint 2010 and SQL Reporting Services 2008 in 6 easy steps
• SharePoint 2010 & SQL 2008 Reporting Services Integration (forum question)
• Error message when you try to access a server locally by using its FQDN or its CNAME alias after you install Windows Server 2003 Service Pack 1: "Access denied" or "No network provider accepted the given network path"
• Recommended configuration for Verbose Logging in Reporting Services