If you have configured email actions, adding users or just testing the email settings, emails should be sent from the instance. If emails are not delivered, first check the email worker log in Unomaly using this command:
unomaly logs celery
That will produce a log of everything that the celery worker has been doing, including email. Normal email log messages will look something like this:
Dec 13 09:46:39 deploy-prod celery: [2018-12-13 09:46:39,506: INFO/Worker-8] unomaly.celery.tasks.notifications.notify[None]: Connecting to smtp-relay.example.com...
Dec 13 09:46:39 deploy-prod celery: [2018-12-13 09:46:39,731: INFO/Worker-8] unomaly.celery.tasks.notifications.notify[None]: Email has been sent.
If you are not seeing "Email has been sent", there is usually an error message. The reason could normally be incorrect credentials, wrong sender or connectivity issues.