I have configured the email account correctly, following the office 365 suggestions and set the port to 587, security set at STARTTLS, yet it gets me this error. Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) smtp.office365.com is unknown. The server may be incorrectly configured. Please verify that your Outgoing server (SMTP) settings are correct and try again. The funny thing was this happens from time to time, sometimes I could send an email out with no problem, but sometimes I got this. Any help would be appreciated. Thanks!.