Hello.
This is a recurring problem, in all versions of Fedora, not just Silverblue. Unfortunately, there seems to be no tune-up between Chromium maintainers and of libs-media-freeworld.
Usually this problem persists for 48 hours or less. Please try again in a few hours.
If playing such media is really urgent for you, you should try installing Firefox Nightly on flatpak, from here: https://firefox-flatpak.mojefedora.cz/