0x800CCC0E : Outlook SMTP error when sending mail

One of my customers was getting this error message when trying to send e-mail:

The connection to the server has failed. Subject ‘New email address’, Account: ‘mail.example.com’, Server: ‘mail.example.com’, Protocol: SMTP, Port: 25, Secure(SSL): No, Socket Error: 10013, Error Number: 0x800CCC0E

The problem – some ISP’s block port 25 for all but their own SMTP server. I’m not quite sure why they do this, but it’s annoying! Anyway, to fix the problem, the user needs to either use their ISP’s SMTP server to send e-mails, or they need to change their outgoing SMTP port from port 25 (default) to port 26. You will need to ensure that your mail server is set up to listen on port 26 first though – it is quite common these days, but not all do. If you run a cPanel/WHM server, you can enable port 26 in Exim by logging in to WHM and going to “Service Manager” in the menu. From here, you can set Exim to run on port 26 as well as port 25. Don’t forget to unblock port 26 in your servers firewall!