"Connection Refused" when Submitting Email Form

Looks like we need email configuration of some sort. Testing here:
http://unicef-rapidpro-for-health.herokuapp.com/contact-us/
This happens on form submission.
Environment:

Request Method: POST
Request URL: https://unicef-rapidpro-for-health.herokuapp.com/contact_form/

Django Version: 1.11.12
Python Version: 3.6.4
Installed Applications:
['django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.sites',
 'django.contrib.sitemaps',
 'djangocms_admin_style',
 'django.contrib.admin',
 'django.contrib.redirects',
 'cms',
 'menus',
 'treebeard',
 'sekizai',
 'filer',
 'easy_thumbnails',
 'django_countries',
 'djangocms_text_ckeditor',
 'djangocms_link',
 'cmsplugin_filer_image',
 'django_select2',
 'storages',
 'rh.apps.meta',
 'rh.apps.content',
 'rh.apps.icons',
 'rh.apps.case_studies',
 'rh.apps.steps']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'whitenoise.middleware.WhiteNoiseMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'django.middleware.locale.LocaleMiddleware',
 'django.contrib.redirects.middleware.RedirectFallbackMiddleware',
 'cms.middleware.utils.ApphookReloadMiddleware',
 'cms.middleware.user.CurrentUserMiddleware',
 'rh.middleware.BetterCurrentPageMiddleware',
 'cms.middleware.toolbar.ToolbarMiddleware']

Traceback:

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "./rh/apps/content/views.py" in contact_form
  28.         mail_managers('Contact', message=message)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/mail/__init__.py" in mail_managers
  118.     mail.send(fail_silently=fail_silently)

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/mail/message.py" in send
  348.         return self.get_connection(fail_silently).send_messages([self])

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/mail/backends/smtp.py" in send_messages
  104.             new_conn_created = self.open()

File "/app/.heroku/python/lib/python3.6/site-packages/django/core/mail/backends/smtp.py" in open
  64.             self.connection = self.connection_class(self.host, self.port, **connection_params)

File "/app/.heroku/python/lib/python3.6/smtplib.py" in __init__
  251.             (code, msg) = self.connect(host, port)

File "/app/.heroku/python/lib/python3.6/smtplib.py" in connect
  336.         self.sock = self._get_socket(host, port, self.timeout)

File "/app/.heroku/python/lib/python3.6/smtplib.py" in _get_socket
  307.                                         self.source_address)

File "/app/.heroku/python/lib/python3.6/socket.py" in create_connection
  724.         raise err

File "/app/.heroku/python/lib/python3.6/socket.py" in create_connection
  713.             sock.connect(sa)

Exception Type: ConnectionRefusedError at /contact_form/
Exception Value: [Errno 111] Connection refused
rapidpro / chpro-microsite

"Connection Refused" when Submitting Email Form #82
