Virtual Reality project HTML5 output has black background!

I have created a Virtual Reality project.

When I publish the ouptu and view Index.html5 file, it shows up in black background. Hence the content is not visible.

However, when I preview the output or open the output through the dialog that appears soon after publishing [Do you want to open the output?]; it displays with correct background. 

This way, I need to every time generate the output to view it correctly. I cannot rely on the Index.html5 file to open the output.