This can happen if the font that is requested is corrupted or otherwise can't be accessed, possibly because the font is under control of a third-party font manager and is located in a non standard location. You can check in Font Book for font issues like corrupted and duplicate fonts.

You can check in the Rules tab in the right panel in the Inspector what font-family is used for selected text. You can check in the Font tab in the right panel in the Inspector what font is actually used because Firefox might be using a different font than specified by the website.

• https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Edit_fonts

See also these threads about similar font issues on Mac.

• /questions/1292109 Fonts replaced with question marks in boxes
• /questions/1268528 when I type the number 9, the underscore symbol appears (long dash)
• /questions/1278708 Text of website https://apod.nasa.gov/apod/ is missing the charakters x, y, z but only in lower case where x is not simply missing but replaced by "

(accidentally marked as solved) Should the rendering in other browsers also be wrong? But it is not.

hello boris,

both sites rendered ok for me.

but have no idea they dont for you.

try deleting the cookies for the sites.

then revisit them.

Make sure you allow pages to choose their own fonts and that you do not block remote (downloadable) fonts.

• /questions/1325619 Weird font on some website's

Possible issue with Roboto Regular font-weight:400 wrong; Roboto Medium font-weight:500 OK

• https://fonts.google.com/specimen/Roboto

See also this bug report:

• 1662983 - Roboto web font not rendering properly

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)