User can't download quicktime via "view source file" in overlay player

Hi,

none of my users seem to be able to download a source file from the overlay player.
image

If they click on the gear in the lower right, then click on “view source file”, one gets a blank page with no info (on OSX), the other gets an error like this (on windows):
image

This happens even when I promotes a manager to admin for testing.
The respective user entities all have the “file access” option checked as well as “can see media download links in SG”.

What am I missing?

Cheers,
frank