Outgoing Server errors using Apple Mail with a Custom Domain

28. October 2013 · Write a comment · Categories: Hotmail, Outlook.com · Tags: , , ,
I receive the following error using Apple Mail v4.6 on OSX v10.6.8:

Cannot send message using the server...
Sending the message content to the server failed.

I am using Outlook.com servers with a Custom Domain email address. I have no problem receiving emails, but I cannot send emails. The outgoing server settings are:

Server Name: smtp-mail.outlook.com
Use default ports (25,465,587) - I have tried using Custom Ports 25 and 587 but that didn't help.
Use SSL
Authentication: Password
*** email address ***
*** password ***

Please let me know how to fix this. Thanks. 

UPDATE: I forgot to mention that the Account Type is IMAP