I am having the same problem with downloading vector file previews. Will not work in Chrome, Firefox, or Safari. Photo previews will download. Using Mac with latest software updates.
We apologize for the inconvenience caused to you. Currently, the vector previews are unable to be downloaded. The licensed vector files can be downloaded but the previews cannot. We're aware of this issue and are working on a fix.
The fix for Vector Previews is deployed and live. You may now download the vector previews.
Feel free to update this thread in case of any additional questions.