When clicking on the Play Now button from your studio account, some browsers don't show the video. This is a browser / flash thing. Here is the fix.
The Play Now feature is not the culprit. It is something to do with certain browsers, flash, and permissions. To fix this, you need to enable Flash to play.
For Chrome, for example, if you click the Lock or Info icon in the address bar. You will see flash in the drop down. Set to Always Allow and reload and it works.
Here's more info with additional instructions for Chrome on desktops, tablets, and smart phones https://support.google.com/chrome/answer/6258784?co=GENIE.Platform%3DDesktop&hl=en.