Mail report allows you to send an email with a summary of the files passed from the next or error result of the previous node. Mail report can be used with an email account that either does not have two factor authentication set up or has an app specific password set up for ConneX. To set up an app specific password for a Gmail account reference this link.
For Gmail the host should be smtp.gmail.com and the port should be 465. For other mail services, look up the mail server settings for your email host and use those.