Ai vers 28.7.1 - Glyphs show up, but cannot be selected

Using Illustrator version 28.7.1...  I am working on a document from approx. 1-1/2 years ago that I created and saved.  Trying to work with it today, the type Glyph choices (that were saved 1-1/2 years ago, using a font that owned then, and that I still own) do show up.  But, when you attempt to select the glyph of your choice by double-clicking on it, Illustrator will not allow the change to be made; in fact, nothing happens.  I did check the Glyph window, and "Alternates for current selection" is chosen, as per a suggestion that I saw from the Adobe Community.   I also checked my Illustrator -> Preferences -> Type, and the box for "enable missing glyph protection" is checked, which was also a suggestion from the Adobe Community.   In case it matters, the font is called "Balford Shadow", and was purchased from "My Fonts".  I don't understand why I was able to save this project with the desired glyphs intact 1-1/2 years ago, but today when I opened it, the glyphs I chose back then no longer show properly in the artwork, and although they show up as choices in the glyph window, they cannot be selected.  Please help if possible!  Thank you very much!