unable to send emails to Yahoo

[Andreas Freyvogel]

I am having a weird situation in the fact that on occasion we are unable to
send emails to recipients at Yahoo.

The error we are getting is:

host mx2.mail.yahoo.com[64.156.215.6] said: 552
    Put ,E=\r\n at the end of Mether, Mtcp, or Msmtp in sendmail.cf if you
are
    using Solaris 2.5 (fixed in 2.5.1). I cannot accept messages with stray
    newlines.  Many SMTP servers will time out waiting for \r\n.\r\n.


We are running on RedHat with Cyrus and Postfix. Anyone ideas from anyone
would be greatly appreciated. The tough thing is that it does not happen
every time.


Thanks for any help,
-Andreas