The videos do not play after being inserted into the knowledge article. They appear as a black screen.DescriptionThe videos do not play after being inserted into the knowledge article through the type 'video library'. They appear as a black screen.Steps to Reproduce Please make sure that html sanitizer for the article body field of the article is off (html_sanitize=false)1. Open a knowledge article record in a Knowledge Base2. Click "Insert/Edit" video button in the tinymce editor to add a video into the "Article Body"3. Choose "Video Library" as Type in the popup opened and click "New" button to upload a video into the library. Choose file to upload and then click Upload button to upload your video.4. You see a blank video in preview in the popup window after the upload progress is completed5- Click OK to close the popup6- You see a blank screen/video in the article body.Expected behaviorSeeing a playable videoActual behaviorSeeing a black screenWorkaroundAttach the video to the KB article using a paperclip icon and then click on the insert/edit video button in HTML and select type as 'attachment', this allows the video to be playable on the KB article.Related Problem: PRB1405792