This error is shown when you use an incorrect range operator in a formula, or when you use an intersection operator (space character) between range references to specify an intersection of two ranges that don’t intersect. An intersection is a point in a worksheet where data in two or more ranges cross.
If you’ve used an incorrect range operator, make sure you use:
A colon (:) to separate the first cell from the last cell when you refer to a continuous range of cells in a formula. For example, SUM(A1:A10) refers to the range that includes cells A1 through cell A10.
A comma (,) as the union operator when you refer to two areas that don't intersect. For example, if the formula sums two ranges, make sure that a comma separates the two ranges (SUM(A1:A10,C1:C10)).
If you get this error because you’ve used a space character between ranges that don’t intersect, change the references so that ranges do intersect.
For example, in the formula =CELL(“address”,(A1:A5 C1:C3)), the ranges A1:A5 and C1:C3 don’t intersect, and the formula returns the #NULL! error. If you change this to =CELL("address",(A1:A5 A3:C3)), the CELL function returns the cell address at which the two ranges intersect—cell A3.
Tip: If error checking is turned on in Excel, you can click next to cell that shows the error. Click Show Calculation Steps if it’s available. Then pick the resolution that works for your data.