Conditional formatting with empty cell

Hi,
I want to use conditional formatting on a column ('A') to highlight cells that do not have a match with any cells in a specific range.
So I've made a range called 'AcceptedData', which contains a couple of cells with text.
Also included a blank cell in the range, since I do not want blank cells to be highlighted.

Then I used this conditional format forumla on column A.
=COUNTIF(AcceptedData;A1)=0

But it doesn't seem to work. The blank cells get highlighted.
How do I get around this?