A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data
Though I believe I may be wrong, as I would open the regular spreadsheet file, that's where I would open a data connection with that sheet in the same file.
It used to work fine, but somehow when I tried open a new file from scratch and opening the data connection of that file in a different file, it worked.
To simplify this, the file name is "Test.xlsx" and the data is in "Sheet 1". I tried clicking "Get Data" > "From File" > "From Excel Workbook" in which I would go to "Test.xlsx" and it would give me that error popup message. Instead, I opened a new file all together, followed the same steps, and it worked. Maybe that has something to do with it?