Can't sign in to Dropbox app on Mac despite correct password

I am trying to connect to a Dropbox Team account on a MacBook Air running macOS Mojave. There is already a private Dropbox account which works correctly on the computer. When I try to sign in to the Team account and I enter the account password I am left at the login window with the square Dropbox logo icon with the moving lines. The lines keep moving as though something is happening, but after a long time the window just disappears without signing me in to the Team account. I have done the full erase and reinstall of the Dropbox app (deleting ~/.dropbox, etc.) with no change in the behavior - the private Dropbox account works fine, the Team account hangs while authenticating. When I sign in to the Team account on the computer using a web browser it works fine, so I know the password is correct. Neither the private nor the business account use 2FA, so that is not an issue. In the website account settings under Security I can also see that the computer becomes "linked" while the login window is hung. I can unlink the computer, quit Dropbox, and try to sign in again with the Team account and the computer again becomes linked but without ever completely signing in or completing setup on the computer. The Team Dropbox folder never appears in ~, though the private Dropbox folder was created with no issue. I can manually create a folder in ~ with the expected name and that also works fine, so I don't think it's a filesystem permissions issue. How can I diagnose this further?