"Create vectors from each column using column names" option greyed out, how to access it?

I have a script to pull an n number of variables from a spreadsheet and have it create .mat for the respective variables selected. I have as seen in the photo two column vectors each have a column header, red then green. In the past I was able to use the "Create vectors from each column..." option but am now not able to. My spreadsheet has not changed nor has any of the script. I am not sure why I am not allowed this option nor what to do to allow me.

[Stephen23]

@Noah Mac: please upload the spreadsheet by clicking the paperclip button.

[Noah Mac]

spreadsheet uploaded, sheet "NM" was used

Answer 1

[Noah Mac]

I copied the excel sheet into a new one (revised sheet) with the exact information, used the "revised" one and it worked. It appears that the original excel sheet was corrupted in some way.

Answer 2

[Steven Lord]

Are the column names in the spreadsheet valid MATLAB identifiers (if you passed them to isvarname would it return true?)

[Noah Mac]

yes, column names are red and green, both return true.