The 'Target' in a Worksheet_Change event is the cell address of the cell you manually changed (or via code), not one that changes via formula/calculation. So in this case, the Target.Address would never be D2 as you're only changing cells starting in row 5 (or on other worksheets).

You would likely need to use the Worksheet_Calculate event, and adjust the code to check the value in 'Test User'!D2 upon each calculation attempt.