Link to the webpage with the video, please?

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then make sure such extensions do not block content. There is security software that can interfere with loading content, so check that as well. *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes ---- Firefox 42+ has a Tracking Protection feature that is enabled by default in Private Browsing mode. When you are in private browsing mode then Firefox can show a shield icon at the left end of the location/address bar that some content is affected. You can disable this feature in "Options/Preferences > Privacy" or via the about:privatebrowsing page that get when you open a New Private Window. *Options/Preferences > Privacy: "Use Tracking Protection in Private Windows" *https://support.mozilla.org/kb/tracking-protection-firefox *https://support.mozilla.org/kb/control-center-site-privacy-and-security-firefox