The link you post needs to be the actual URL of the Youtube page (ending in 'youtube.com') NOT the link generated by the 'Share' button (which ends in 'youtu.be').
The only way I managed it from a mobile was changing to the YouTube desktop site and copying that link. The thread where we practised hasn't been moved over x
You are better googling the title of the Youtube video, and then lookat the results under the video tab in Google. Click on the result picture and copy the link there.
Pate it directly into your ABs Answer text box.