Hi Alejandro,
First, please remove this CSS block from your Theme Options > CSS
That is not correct commenting and causing errors on the entire Theme Options > CSS, use this tool to check your custom CSS.
Comments in CSS
Then please remove this from your parent X style.css file, and add it on the top of Theme Options > CSS. Parent X style.css file is not a place where you add custom CSS, because it will be wipe out when the theme update, you might want to use a child theme instead.
@font-face {
font-family: Mondia;
src: url(http://www.bristolphotofestival.org/wordpress/wp-content/uploads/2020/03/font.woff2);
font-weight: normal;
}
I don’t see the font Mondia getting loaded on your site, that means there is wrong on that @font-face declaration. One of that is the font source (src) URL, please check that.
Then follow this guide here on Using @font-face
I think the reason why this font working on your desktop is that this font Mondia is installed on your desktop locally.
Hope it helps,
Cheers!