SSRS 2014: The report parameter has a DefaultValue or a ValidValue that depends on the report parameter. Forward dependencies are not valid

Question

After trying a lot on Google, I ran out of luck and here I am seeking your help. I am trying to create a dataset in SSRS using a Stored Procedure and I am having hard time. Could someone please shed me light of what I am missing?

Here is the how my Stored Procedure looks like:

    CREATE PROCEDURE [dbo].[usp_GetUserData](@ReportRunDate DATE        = NULL,
                                         @ReportName    VARCHAR(50) = NULL)
AS
     BEGIN
         WITH CTE
              AS (SELECT [USER_ID], [Name], [Address], [DOB], [Status], [UserType], [DateAdded]
                  FROM [dbo].[User_Information]
               WHERE [DateAdded] = @ReportRunDate)
              SELECT *
              INTO #UserReport
              FROM CTE;
         IF(@ReportName = 'Internal')
             BEGIN
                 SELECT [USER_ID], [Name], [Address], [DOB]
                 FROM #InternalReport
                 WHERE [UserType] = 'Internal';
                 SELECT *
                 FROM #InternalReport;
             END;
         IF(@ReportName = 'External')
             BEGIN
                 SELECT [Name],[Status]
                 FROM #ExternalReport
                 WHERE [UserType] = 'External';
                 SELECT *
                 FROM #ExternalReport;
             END;
     END;

I've changed the order of parameters as mentioned by many people in SO but that didn't help either as well.