Only cells A5:A7 in your file are proper times, the rest are text, looking like times/numbers. So the conditional formatting doesn't work.
If you select cell A1, press F2, then press Enter, Excel will convert that cell to a number and move to the next cell (it's just you re-entering the cell to edit it and pressing Enter without changing anything).
You could repeat the key presses all the way down the column (tedious) butyou can also select all the cells and type:
Code:
Selection.Value = Selection.Value
and press
Enter in the
Immediate pane ofthe VBE to do it
en masse.
Better is to perhaps to change how the data gets there in the first place; how are you getting that data there at the moment?