Analysis :: Data Masking For Dimension Attribute Based On User In SSAS 2014 Multidimensional?

I am trying to implement data masking based on user login and not sure why this is not working. I have the dimensions DimBrand, DimProduct and DimUser. I should mask the BrandCode with 'XXXX' nothing but in the report all the BrandCode should appear but few of the code will be masked if the user is not belongs to that group. I have a fact table FactProduct in this. In the cube I created all these 3 dimensions and the fact table. I created a new dimension DimBrandMask and I separated the code over there with a relationship with the actual DimBrand dimension. In the cube a reference relationship is set up with the measure group. Created a role with read access.

In the dimension data tab of role I put the below MDX to allowed set.

NonEmpty([DimBrandMask].[Brand Code].Members, (StrToMember("[DimUser].[Login Name].[Login Name].[" + UserName() + "]") ,[Measures].[Dim User Count]))

And in Denied Member set i put the below MDX

IIF( (StrToMember("[DimUser].[Login Name].[Login Name].[" + UserName() + "]"), [DimUser].[Access Right].&[False]), NONEMPTY( [DimBrandMask].[Brand Code].Members,(StrToMember("[DimUser].[Login Name].[Login Name].["
+ UserName() + "]"), [DimUser].[Access Right].&[False], [Measures].[Dim User Count])),{})

Note I created one measure group from the DimUser table and the measure [Dim User Count] is used in the above query.

I am expecting some result like below

Brand      BrandCode           Count
Brand1      b1                       6
Brand2     XXXXX                  5
Brand3     XXXXX                 10