I don’t think this issue has been raised before, but I can indeed reproduce it on xwiki.org.
However, it seems to work fine when I install the extension on a local instance, so maybe one of the page’s extension is missing some rights? Could you try uninstalling it and installing it again on your own instance? (You should not lose any entry by doing this)
It looks like that extension requires programming rights for cloud tags (which an administrator on the main wiki would have, but not an administrator on a subwiki).
Now, that sounds like a bug, it doesn’t look like that should be a requirement there, so I’ll open an issue to track that.
In the meantime, I’ll give you a few directions since I don’t know your actual setup:
if you are on a subwiki, you could try reaching out to a main wiki administrator and ask them to either reinstall the application, or edit FAQ.JSON, which should fix the permissions
or if you are a main wiki administrator, you could try to give yourself programming rights