Document preview not displaying

Hello,
Almost ready to go live with my site and document previews have stopped working for my packages. Do you have any troubleshooting tips for document previews?

Thanks!

Steve.

I mistakenly posted this problem to this forum . . . Shaon helped me over on the Pro support forum by suggesting to do this:

Shaon wrote:

Please open wpdm-functions.php, replace http://docs.google.com with https://docs.google.com .

This resolved the problem.

Thanks!