New machine, so brand new bluecherry installation. Instead of leaving bluecherry MySQL password blank, I entered a password (sequence of letters, space character, sequence of letters). Installation completed, but then when attempting to connect to localhost:7001, got LANG_DIE_COULDNOTCONNECT from function connect() in class database.
Started fresh by "apt-get --purge remove bluecherry mysql-server" then "apt-get install bluecherry". Selected same password. Got same results.
Started fresh again with the same commands, and left password field blank this time, in order to get the auto-generated password. Was then able to connect to port 7001 as expected.