When you use custom authentication in Microsoft SQL Server 2014 or 2016 Reporting Services (SSRS), you experience a System.NullReferenceException error when you render reports, and you receive an error message that resembles the following in the Reporting Services log:
library!ReportServer_0-1!277c!Date-Time:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.InternalCatalogException: , Microsoft.ReportingServices.Diagnostics.Utilities.InternalCatalogException: An internal error occurred on the report server. See the error log for more details. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.ReportingServices.WebServer.Global.Application_EndRequest(Object sender, EventArgs e)
--- End of inner exception stack trace ---;
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.