Before you add URL parameters, remove :iid=[#] at the end of the URL.
:embed=yes works for me.
You were able to see your recent Workbook content menu embedded into a dashboard?
Not sure if you need all of this but I have used this in the past to get this to work: replace tableauserver.com with your server url
*Note: It will not look like it works in desktop but it should once it is on the server.