var options = { videoId: 'KGfxtbiNoLk',
start: 1, mute: false, repeat: true };
That is the var parameter when doing HTML
i do know recently autostart in Chrome has been hit or miss with Youtube (sometimes starts sometimes don't)
So maybe the embed values for youtube are affected the same way could clear up (html page method i am using has been working ok)
Try using
https://www.tools4noobs....ne_tools/youtube_xhtml/
or some of the more recently updated similar websites by googling "youtube embed code generator"
see what kind of parameters they come up with for autostart.
Peace