Writing an IF statement in Excel

I have inserted a check box (form control) with the title "wall". Next to this I have the cell stating "False" if unticked and "True" if ticked.

Next to this are two cells with the dimensions of the wall "length", "height". Lastly is the cell containing "area of the wall".

I want to write an IF statement in the "area of the wall" cell so that when the check box IS ticked, the area of the wall is printed, and if it is NOT ticked it prints N/A.

If have written:

=IF((C2="TRUE"), (D2*E2), ("N/A"))

All that happens is the cell reads N/A, no matter whether the box is ticked or not.

Any help please on how to correct this?