Hi i am getting this error when i try run my report. Any help will be appreciated. Thank you

 

An unexpected error occured while running the Report

Error Details

Object reference not set to an instance of an object.

SELECT [TestTab].[NAme] AS [Name], [TestTab].[Phone] AS [Phone], [TestTab].[Address] AS [Address] FROM [TestTab] WITH (READUNCOMMITTED) Group By [TestTab].[NAme],[TestTab].[Phone],[TestTab].[Address] ORDER BY [TestTab].[NAme]