2nd time I've used; i can hear e.g. Spotify play, so I know my system otherwise is working. I can hear the video natively in e.g. windows media player.
Without a lot more detail from you we are extremely unlikely to be able to help you! After all, we know nothing about your computer, nor even the exact program and version you are running.
Please read this post and give us ALL the information requested there. And don't forget to check the version of the program you are using, normally found under Help>About.
Also, can you find, download and install the free MediaInfo utility, point it to the file you are having problems with and post here the results of the Text view.
The fact that Spotify works normally and that WMP can play your file may be irrelevant but the problem could be simply that the audio of your file is muted when played in whichever Magix program you have, or there could be a codec problem. But without the extra information from you we are simply guessing!