Brother MFC-B7715DW Online User's Manual page 319

You must configure your machine's SMTP communication method to match the method used by your email
server. For details about your email server settings, contact your network administrator or your ISP.
In most cases, the secured webmail services require the following settings:
SMTP Port
Server Authentication Method
SSL/TLS
Related Information
• Send an Email Securely
25
SMTP-AUTH
TLS
313