Im having a similar problem, my embed shows in the back end but on the live site nothing shows. I’ve used the built in add media feature of wordpress. I’m not sure if this was an issue or if a fix have been issue. I created a password protected page, so all audio uploaded on that page is only available to preview for that particular client. I say that to say, a public hosting such as sound cloud will not suffice. Thank you for the assistance in advance.