If you are like many of our customers, you would like your "Reviewers" to be able to download proofs for easy use or to share. (if you don't want this, ignore the article)
If this sounds awesome to you, go ahead and:
Click on your user icon and select "Account Admin"
Click and open the "Proof Settings" tab
Find the "Proof Downloads" section and toggle on the "Collaborators" option.