Mysql2::Error::ConnectionError: Can't connect to MySQL server on '' (115)

I followed your instructions in trying to set up a mail server using Postal. When I get to the step of initializing postal I am getting the following error:

Pulling web … done
Pulling smtp … done
Pulling worker … done
Pulling cron … done
Pulling requeuer … done
Creating postal_runner_run … done
Initializing database
Can’t connect to MySQL server on ‘’ (115)
Couldn’t create ‘postal’ database. Please check your configuration.
rake aborted!
Mysql2::Error::ConnectionError: Can’t connect to MySQL server on ‘’ (115)

Check your postal configuration file. You must have entered a different password.