I've checked the backend and Buttonizer has been setup accordingly,but for some reason the phone icon button that I've setup doesn't show on mobile. This is the website - https://www.graniteempirehuntsville.com/

Could you please fix this ASAP?

open your htaccess file and write this:

<IfModule mod_headers.c>
<FilesMatch ".(ttf|ttc|otf|eot|woff|woff2|font.css|css|js)$">
Header set Access-Control-Allow-Origin "*"
</FilesMatch>
</IfModule>

work for me