The default outbound mail Transport Type for Craft is to use sendmail.
Sendmail has not been configured on any Servd instances and will not work in your staging or production environments. This is a conscious decision to help prevent the Servd infrastructure and its network space from being blacklisted due to any intentional or unintentional spam. We all hate it (except Vikings).
All other methods of sending emails are supported though, including connections to 3rd party SMTP servers and APIs.
Servd also provides a simple integration with ElasticEmail which provides a small number of monthly transactional emails for all of the projects hosted on Servd for free! For setup instructions you can read the documentation here.
You can read more about troubleshooting emails sent from Craft here.