I'm using Thunderbird on an Ubuntu 14.04 Desktop, when I try and send an email from my outlook.com email account I get this message, Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp-mail.outlook.com timed out. Try again. It only seems to happen when I'm connected to the VPN, I'm able to send emails by logging in to the outlook.com web portal regardless of whether I'm connected to the VPN or not. I found the IP address for the SMTP server by running an nslookup with the server name & I got this output, Non-authoritative answer: smtp-mail.outlook.com canonical name = smtp.live.com. smtp.live.com canonical name = smtp.glbdns2.microsoft.com. Name: smtp.glbdns2.microsoft.com Address: 65.55.176.126 So I went in to account settings & changed the server name from the host name to the IP address but I'm still having the same issue. Any ideas as to what is wrong?