Play several audio tracks at the same time

Hey guys!

So I have a little problem:

I would like to start playing two music tracks at the same time. I already succeed to do that a few weeks ago, but for some reason it doesn't work anymore. Let me explain:

It still works on the first layout that I created a few weeks ago (actually I can run 5+ audio tracks at the same time).

BUT when I tried to do that on another layout or even another project and it doesn't work :(

Any idea why?

Thank you very much for your help!

(Do not hesitate to tell me if my english sucks haha)

EDIT : Ok... So I exported the project as a .exe, and it works.

Apparently it doesn't work in preview mode for some reason...

I'll keep looking into it...

Where do you test? Chrome can't handle more than one sound at a time on my system.

I test on Chrome, but I always did and that's why it is weird :/

Weirder is that my first layout works with my 5 musics tracks at the same time and not the new things (layout and projects) that I'm doing.

EDIT :

Ok... So it kinda works. BUT, the second track always take several seconds to play, and it shouldn't. Again, I'm still looking into it, hoping to find where's the problem.

EDIT 2:

Oook, so I tried with Firefox and it works well. I don't know what's going on with Chrome, this is weird. I can't find an explanation. Note that I only tried with the local preview, I didn't try it online (uploaded on a FTP or whatever). I'll let you know about that!