When using the Insert Stuff framework to add a YouTube video/other embedded media in the Content using Internet Explorer, Mozilla Firefox, or Google Chrome, the browser blocks the content because it is not considered secure, without informing the user that there is actually an invisible block around where the media should be. This makes it appear as if the insert failed even though the browser is actually blocking the content.
To resolve this issue, ensure that you have enabled the ability to view unsecured content in your browser.