Soundcloud SDK with Heroku

I am currently developing a web application in NodeJS and prefer to use Heroku for hosting. Now, before I started using Heroku, I would just test my application locally and everything worked fine.

When deploying my app, my soundcloud iFrames didn't work anymore. I check the source code at F12 to notice that my app did not successfully invoke the Soundcloud SDK. ( http://connect.soundcloud.com/sdk.js )

I figured I could put the file in my application, so I did, but it doesn't work because the file cannot make calls to the dependencies of other files. No matter when you follow the documentation; https://developers.soundcloud.com/docs/api/sdks , he recommends just bundling it externally.

Now, my question and problem is: Why can't my application successfully invoke the JS file when deployed, but works fine locally?