When our client (Network Affiliate) purchases SMTP, they will get Domain/IP Address SMTP, port, Type SMTP, User Name SMTP, which needs to be filled in the Email settings section. If you are using QQ server, you need to make sure that SMTP user name and username of email address should be consistent, Otherwise, it will be considered as spam by QQ, and rejected. After you filled all the SMTP details, you can test it by clicking on Test button. If the test is successful, the email notification will be sent automatically as per the notification settings.
(Note: If you have set the SMTP and test successfully, however, there are some delays in the email reception, please check if the SMTP service is stable.)