PowerBI Report Buildder: How to make a conditional formatting for matrix by group?

I currently have a report produces a matrix, displayed per user group.  (1 user group per page, with 35 user groups/pages)

I want to highlight the row in pink in this condition: 

=IIf(Fields!CountFailures.Value>=1,"Pink","White")

However, it is not showing any colour.  Please help! (I am using PowerBI Report Builder... should be same as SSRS)