Just an announcement in case anybody else has the same problem:

I just installed Armory on a relatively new Mac (running OS X Mojave, not the brand new Catalina).  Armory did not work, it could not open the app.  Starting the relevant script inside the Armory.app folder showed that the error was that a library in /usr/local/opt/openssl/lib could not be opened, that folder was missing.

Installing openssl with Homebrew (see https://brew.sh) fixed it!

It seems to be an error in building the MacOS executable, where OpenSSL has not been bundled as it should have been.