demo like below mentiond site,

amitkadivar.xyz

media file usefull links when DEBUG=False

https://stackoverflow.com/questions/44555187/django-media-files-not-showing-with-debug-false-on-production-django-1-10

how to connect django with dropbox install
pip3 install dropbox django-storages create app FileStorege

INSTALLED_APPS += ( 'storages', )

DEFAULT_FILE_STORAGE = 'storages.backends.dropbox.DropBoxStorage'

DROPBOX_OAUTH2_TOKEN='DropBox-access-key'
DROPBOX_ROOT_PATH='nameofyourapp'
MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media').replace('\\', '/')

FieldMoreDetail

models.py

replace FileField to ImageField or any other field

urls.py

Send mail using Gmail

use this blog for put settings

follow this link for send mail if you got error in live

hosting and add custome domain in hroku

follow this link to add custome domain

heroku domains:add www.yourdomainname.com

add cname in godaddy Add cname and put type :- cNAME Host :-www points to:- yourherokuapp.herokuapp.com

and type in cmd host www.yourdomainname.com or any other doamin name

it's work for me more detail here