Had sent an e-mail with 11 attachments 350k to 400k each to a couple of people. Reworked the email and added another 2 attachments and tried to send but got error message.

Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

Subject ''
Server: 'smtp.east.cox.net'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: SMTP
Port: 465
Secure(SSL): Yes

Tried to send a simple test email, it also failed. Checked old computer ,Vista, and it would send ok.  Tried to send large email from old computer and got error message same as above. Now neither computer will send windows mail. If I log into my Cox mail account, I can send emails normally from either computer. Rechecked server account settings, called Cox support, everything is normal. Only fails to send, receives ok. 

Two different anti-virus systems, Turned firewall, anti-virus off for test, no help.