An SMTP service is not offered natively as part of Sitefinity Cloud. To enable email notifications via the Sitefinity Cloud web application, you need to configure Notification Profiles. Integration is available with many popular SMTP relay service providers (such as SendGrid and Microsoft Office 365), as well as internal SMTP servers, as long as they are configured to allow SMTP relay from Sitefinity Cloud. If your configuration requires whitelisting your Sitefinity Cloud IP addresses, you can obtain them by contacting Sitefinity Cloud Technical Support.