Downloaded font desapeared of the front panel after use it in many pages

Hello,
I’m doing the “Full site build” couse.
I had download the Playfair font. I did many page with it. Now it have desapeared of the font panel and all text using it no longer have font associated.

That a problem. Is this occur often ?


Here is my site Read-Only: LINK
(how to share your site Read-Only link)