Latest Firefox update causes You Tube to fail to open
iMac running MacOS Mojave version 10.14.5, Firefox 67.0 After updating Firefox found You Tube would not load. Entering a URL, the You Tube logo appears upper left but no You Tube search window. To the right of where it is absent are four light grey circles. Lower down are some more circles and longish rectangles. I have no Firewall, which was one suggestion I came across. I had the problem after the Firefox update and updated Mojave in the hope that this would resolve the issue. Would appreciate any suggestions be presented in clear and simple terms as I don't know much tech jargon.
Additional System Details
Didn't know what this meant but eventually found my way to a section headed 'Manage Your Plugins' where the following appeared:
OpenH264 Video Codec provided by Cisco Systems, Inc Widevine Content Decryption Module provided by Google Inc. Shockwave Flash
Though I didn't really understand what it was about, I clicked the 'Automatically add' button beside 'Troubleshooting information' but it only got some kind of error page which suggested that maybe the link was out of date.
- User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.1.1 Safari/605.1.15