H5P and the Brave browser
Just something I experienced today (April 14, 2021) and wanted to let you know, just in case the number of posts asking for why H5P content doesn't show up increases.
The Brave browser seems to be getting quite popular because its based on Chromium just like Chrome, but comes with many privacy features. However, those seem to be going haywire currently. H5P content flashes briefly, but then is removed from the page. It is blocked. You will have to lower your "privacy shield" to see the content.
The reason for that blocking I don't understand. The "privacy shield" does not list any ads/trackers being blocked (if you don't use them yourself, of course - for instance via YouTube videos, etc.). Still H5P content is blocked. Lowering the tracker/ad blocking from agressive to standard is not enough. Lowering the settings for cookies or fingerprinting isn't enough. You'll have to allow everything, so the Brave browser must assume that H5P is doing something very, very bad :-) Baffles me. Even on my local test system with no outgoing connections (network connection cut) it doesn't show me H5P content. No clue why.
Update (April 15, 2021): Maybe someone noticed a bug and updated some rules or something: H5P content seems not to be blocked anymore on Brave (desktop and mobile).