Original title:  I have not been able to send emails using Windows Live Mail since 05/25.

I have not been able to send emails using Windows Live Mail since 05/25. 

Error message---
unknown error has occurred. 
Subject XXXXX
Server Error: 550
Server Response: 550
Your message does not conform to RFC2822 standard
Server: 'smtpauth.earthlink.net'
Windows Live Mail Error ID: 0x800CCC69
Protocol: SMTP
Port: 587
Secure(SSL): No 

As suggested, I reinstalled Windows Esentials last night, restarted computer, and checked account settings.  Still cannot send emails.