RStudio Server Initialization Error on Mac El Capitan

I have installed RStudio Server using Homebrew on a Mac Pro Server with El Capitan. Then I followed instructions in the INSTALL file. When I launch RStudio Server from the host computer (http://localhost:8787) or remotely, it accepts my username and password but then I get this error: "RStudio Initialization Error: Unable to connect to service". This seems to be common with Linux installs, but none of those posted solutions solve the problem on my Mac. I tried logging in as different users and administrators but I the same error message either way.