Can receive mail but can not send.

Here is an example of the errror message that I get when sending mail........

"The original message was received at Wed, 14 May 2008 07:36:29 -0500
from [12.49.34.210]

----- The following addresses had permanent fatal errors -----
<...........@lisco.com>

----- Transcript of session follows -----
550 5.1.2 <..........@lisco.com>... Host unknown (Name server:
lisco.com.s5b2.psmtp.com.: host not found)"

This problem showed up just a few days ago. I am on Vista with Windows Mail.
I can receive but not send mail.

Post in reply to: Greatone100

This lisco.com?

http://www.lisco.com/

Such a message can indicate that either the sender's internet provider or
the
receiver's internet provider has decided to block all email to or from the
other.
These suggests that psmtp.com may be involved in such a blockage:

http://forum.spamcop.net/forums/lofi...php/t1238.html

http://forum.spamcop.net/forums/lofi...php/t1544.html

http://malwaredomains.com/?p=161

Someone in charge of fixing the problem may need to go here:

<http://www.postini.com/webdocs/admin_spe_cu/wwhelp/wwhimpl/common/html/wwhelp.htm?context=Help_SPE&file=trouble_mx.html>