Dropbox is changing its link format for security reasons, your old links may no longer work and you might have to generate new ones.

Only found this out because a friend mentioned the commission folder refs I've used for years were going to an error message.

If you run into this issue with your/someone else's ref folder, that's probably what's going on and you'll need them to generate you a new link.

Referenced documents:
https://help.dropbox.com/share/force-download
https://www.dropboxforum.com/t5/Create-upload-and-share/Shared-Link-quot-scl-quot-to-quot-s-quot/td-p/689070