Office 365 Email Legacy below TLS 1.2 (Cloud)
VM Cloud PMS only supports TLS 1.2 and does not accommodate older, legacy versions. For Office 365 accounts with multi-factor authentication enabled, the hotel's standard email password will not work. Instead, you must generate and use an app password in Visual Matrix.
However, some reports suggest that you can attempt to use the older account with the following "SMTP Username" setting: legacy-smtp.office365.mail.com.
For more information, please consult your Outlook Support.