Can you please do the following
1. edit your formula to remove external file references, and still produce the problem
2. upload a copy of that workbook here
3. consider the following quote, from
here:
Tips: Consider one of the newer lookup functions, depending on which version of Office you are using.
- Use VLOOKUP to search one row or column, or to search multiple rows and columns (like a table). It's a much improved version of LOOKUP. Watch this video about how to use VLOOKUP.
- If you are using Microsoft 365, use XLOOKUP - it's not only faster, it also lets you search in any direction (up, down, left, right).