leehinde external mail providers should just work, all you need is the correct config in your project settings.
If your app doesn't seem to be sending mail as expected then try sending mail via the management shell, eg:
cd ~/apps/appname
source env/bin/activate
cd myproject
python manage.py shell
Then do this basic Django email example. You might get an error message that helps.
You can also check your app log at ~/logs/apps/appname/uwsgi.log
for errors.