I am trying to share a folder in Dropbox which I have done several times. I hover over the folder in the Dropbox website and click Share. The Add People box comes up and I have tried adding a name or an email address, and the Share button never becomes active. I am running Tahoe 26.5 on a Mac. I have tried restarting the computer, the Finder, and Dropbox, and I have tried on two different browsers. What is going on?