Firefox browser doesn't load youtube's content, showing only grey for videos and text. The browser console shows a number of errors (I've attached a screenshot of the console). Even playing a YouTube video linked from a web site plays only that video. All other content is greyed out. Safari loads YouTube without problem. iMac 2017 OS is up to date, as is Firefox. What do the errors mean, and is it a problem with my settings? Thank you for any help