In order to use Office 365 SMTP for Rent It Biz Mail Settings, SMTP has to be authenticated in your Office 365 eMail Account. First you must have Microsoft 365 Account with Outlook.
1. Log Into your MS 365 Account Select Apps in upper left hand corner, then Go To Admin. 
2. In User Management Edit a User then Select.
3. Go To Mail then Manage eMail Apps
4. Select Authenticate SMTP
