Excel - Allowing formating on a protected sheet

What am I missing here? I’ve created an Excel workbook that needs to have some but not all of the cells protected. I specifically marked “Allow Users of this Worksheet to Format Columns”. However, one of my users is getting ##### in an unprotected cell and isn’t able to make the column wider because Excel tells her the worksheet is protected.

(Moreover, I formatted the columns to autofit selection and also made sure they were big enough for up to a six digit number. No matter the change, my user is saying they get the #'s in the column. On my end, of course, it looks fine.)

So, my questions are: did I do the protection thing wrong? Did I do the column formatting wrong? Is the column width problem tied to the worksheet being protected? How do I fix this problem? I absolutely must be able to protect certain cells in this workbook!