(By the way, where do you prefer these sorts of bug reports, here on the forums or as a github issue? I feel like I shouldn't be duplicating but I'm not sure what's the best way to reach the devs) Github Issue for this bug #265 (along with the unrelated #255 ) Roll20 uses TLS by default, yay! But the content proxy server ( imgsrv.roll20.net ) isn't set up to deliver content over TLS, so the browsers are complaining. Firefox is the most strict in this regard. For passive content (e.g., images), this isn't a big deal as Firefox allows the content. But for "active" content (e.g., fonts) the content is blocked completely. This makes it impossible to use webfonts in our character sheets on Firefox.