How to send mail with third party domains?
It is possible to send email via SMTP using Outlook's SMTP server. Make sure you have set Swiftmailer to send mail via SMTP.


SMTP server: smtp-mail.outlook.com or smtp.office365.com
Port: 587   
Encryption: TLS


Use your Hotmail address and password to log in. You'll probably need to enter your Hotmail address under "Configuration" -> "Basic site settings".

Your web hosting provider may block outgoing SMTP ports. Check with their support to make sure.

More information:


https://support.office.com/en-us/article/POP-IMAP-and-SMTP-settings-for-Outlook-com-d088b986-291d-42b8-9564-9c414e2aa040
https://docs.microsoft.com/en-us/exchange/troubleshoot/send-emails/smtp-submission-improvements#new-behavior-when-submitting-messages