I am trying to use Office 365 Exchange as the mail transport for CiviCRM, but get this error.
Failed to connect to ssl://smtp.office365.com:587 [SMTP: Failed to connect socket: fsockopen(): unable to connect to ssl://smtp.office365.com:587 (Unknown error) (code: -1, response: )]
I have looked at enter link description here, and links therein which seemed to indicate that a STARTTLS issue was fixed.
Office 365 Exchange has these instructions for SMTP connections: enter link description here
I am running a development system under Windows so don't have a mail server on board, and in any case don't want to overcomplicate things - performance isn't an issue.