80040211

I get this error time after time when I try to send message to my forum.

error 80040211
/forum/functions/functions_send_mail.asp

Im using cdosys, iis6, windows2003 and my isp's smtp.

1 of 5 messages are posted just ok and there is no error messages on the screen. Rest of those post causes errors. Why sometimes messages just posted right and most of times not? Is it my isp's problem? What i can do for this problem?

Thanks for any answers!

-josk