Sound doesn't work?

The sound doesn’t work when I go to preview game, I also played the featured games on GDevelop website that other people have made, still no sound. I have checked my speakers and sound card, working fine. The sound is working on all other aspects of my PC even when I watch YouTube so it’s not Flash Player. So what could be wrong???

I figured it out! You can’t use Internet Explorer, you have to use Fire Fox or Google Chrome