InDesign publish online: Video and music do not play together

Hi everyone,

I'm having a problem with the Publish Online feature in Indesign.

I want to play video (mp4) and music (mp3) together on page load. I've set it all up in Indesign so that the video and music play on page load and that they play together at the same time and it works in the preview, but when I publish online, nothing happens at all. Neither the video nor the music play on page load. 

The thing ist that it works separately, meaning that if I only want a video to play automatically on page load it works and if I only want to play music on page load, it works too! But when I want them to play together on page load, it does not work...

I hope you get what I'm trying to say, I find it hard to explain. Can anybody help me with this?