A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
The problem appears to be that F444 does not contain a number or a text value. It appears to be part of a graphic.
The concatenation operator (&) requires that both left and right operands be text, numbers that can be converted to text, or nul.
Your formula worked fine on my system when I tried all three different values in F44.