Dropbox on new Mac keeps loading under the wrong email address.

I loaded Dropbox on a new Mac. Instead of the current Dropbox account, it keeps loading an old one under a different email address. I have followed these recommended steps, but in #4, Dropbox does not offer the option to sign in again that I can find. I have uninstalled and reinstalled numerous times. I have a paid account. Suggestions? 
"1. Sign out of the app. 2. Open Dropbox.com in your web browser and sign out there as well. 3. Sign in to Dropbox.com using the correct email address. 4. Then try signing back in to the Dropbox app on the computer.