How to avoid a #value error due to source cell being blank but containing another formula

Hi, I am using the following formula:

=IF(AND(D3="",E3="",F3=""),"",D3+E3+F3)

to sum three cells but to return a blank (rather than 0) if all source cells are empty. This works fine in other areas of my spreadsheet where all source cells are either empty or contain numbers, however, in this case, cell D3 contains a very simple =IF(D2="","",(D2)) formula, which when this returns a blank (because D2 is empty), I get the #value error.

Any tips on how to avoid this error, please?

Thanks in advance,

Antony