Your html file should be hosted in some web portal then only it will work I guess. Once you hosted then use the relevant link/url and embed in web object of your dashboard.
Thanks for the advice but I did that already.
Do you have a link to the html file that we can use to try to get it working ?
I host the html on my local machine (http://localhost:8000...) so prob wont work for you.
Apparently, Tableau has some issue with html5 and it won't render audio or video. The work around is publish the workbook on to server.