When I share a Prezi with colleagues via email, some of them only see a blank screen - how to fix this?

I click on the “share” button for my Prezi, then copy the provided link and paste it into an email. Some of the people who try the link have no problem; others get a blank, dark page. And it varies - one person had no problem the first time, but couldn’t see the updated version, and she was on the same computer.

Hi Vera!

I have the same problem. http://prezi.com/tyr3thgj52vm/?utm_campaign=share&utm_medium=copy&rc=ex0share this is the prezi they cant see.

Many thanks