The store owner can also test this feature by sending a test mail, and all the messages, such confirmation message for mail send, error message, etc, will be displayed on the SMTP settings page only. Magento 2 SMTP is a module by which the store owner can easily set up an SMTP server on his Webstore so that all the emails sent through his store will get sent by the selected host. Visit - https://store.webkul.com/magento2-smtp-extension.html