It's been a week I cannot send mails from email@example.com
mail server. Some of my co-workers using hsbox.com mail server have the same problem. hsbox.com can receive mails from yahoo.com.tw but when I reply the mail to the sender the mail just disappeared. One day later I got some delay notices but the mail still is missing. The message is as follow. Please would someone help me out on this problem? I opened a ticket five days ago and fax my issue to the support number but still waiting a reply. Please help.
This message was created automatically by mail delivery software.
A message that you sent has not yet been delivered to one or more of its recipients after more than 24 hours on the queue on carp.lunarservers.com.
The message identifier is: 1IpZ60-0001Zn-1k
The subject of the message is: test08
The date of the message is: Wed, 7 Nov 2007 08:47:51 +0800
The address to which the message has not yet been delivered is:firstname.lastname@example.org
Delay reason: SMTP error from remote mail server after initial connection:
host mx2.mail.tw.yahoo.com [220.127.116.11]: 453 Mail from 18.104.22.168 not allowed - 
No action is required on your part. Delivery attempts will continue for some time, and this warning may be repeated at intervals if the message remains undelivered. Eventually the mail delivery software will give up, and when that happens, the message will be returned to you.