WebApps Report

Hello there,

I created a SSRS report that will be used in WebApps. The SSRS report does seem working fine in Visual studio. But when i add the report to WebApps, it is not working and getting the below error. I am using UserId as the parameter to the report. 

Microsoft.Dynamics.SL.ROIService.ReadReportInfo NullReferenceException Object reference not set to an instance of an object. (Consumer: fe80::b13a:42ae:7510:4320%10)

at Microsoft.Dynamics.SL.WebServices.ROIService.ROIDTO_Read_ReportInfo(String rptNbr, String rptFormat, Guid session_key)
at Microsoft.Dynamics.SL.WebServices.WebMethodPattern.Run[T1,T2,T3,TResult](String methodName, Guid session, Func`4 method, T1 arg1, T2 arg2, T3 arg3)

Appreciate if someone help me on this.

Thanks,

Karthik