Send Emails with PHP mail() in Symfony

Remove all mailer sections from factories.yml in apps/frontend-or-backend/config, then add this code to the "all" section:

mailer:
  class: sfMailer
  param:
    logging: %SF_LOGGING_ENABLED%
    charset: %SF_CHARSET%
    delivery_strategy: realtime
    transport:
      class: Swift_MailTransport