Assuming he is using the right SMTP mail server (the one for his ISP)
you'll need to talk to his ISP.

The error message is saying that his PC has sent a lot of spam. It may
be that his PC is infected with malware that has taken over his PC to
send spam. Start with a thorough cleaning of his PC. See:

Dealing with Unwanted Spyware, Parasites, Toolbars and Search Engines
http://www.mvps.org/winhelp2002/unwanted.htm

Spyware, Browser Hijackings and other Antisocial Tricks
http://inetexplorer.mvps.org/darnit.html

Removing Malware
http://www.elephantboycomputers.com/...moving_Malware

If malware is found and removed, you'll need to ask the ISP to allow his
PC to send again.

Or it may be that his PC has been used to send to mailing lists for your
company and the amount of mail sent exceeds what the ISP allows. In
that case, you'll need to ask the ISP to increase the limit for him.

--

Mike - http://pages.prodigy.net/michael_santovec/techhelp.htm


"fandi" wrote in message
...
my boss oe cant send email with error 550host,localhost is blocked
cause your
cumputer
used to send spams,error code 0x800ccc79,Unfortunately the language is
korean so i only pst the english code...
hope someone can help and mail me to
thx a lot