Preview not working in Articulate Storyline 2

Hi!

I am having problem with the PREVIEW feature of Storyline 2. 

Whenever I try to preview the current slide or project, it get stuck in the loading page (see attached) and won't get through. So what I do is publish the entire project which is taking too long. 

Is this because of the flash player? Not sure how to install as I can't find any installer from the internet.

Hope you can help me. Thank you!