What do I do when I receive an email with the subject “Undelivered Mail Returned to Sender”?
A
Most of the times, this happens when the recipient’s email address is not entered correctly. Please check the recipient’s address again.
If the email address is correct, please check with the recipient by referring to the reason written in the main body of the email.
The following shows the major causes and the place where the cause is written in the email.
■Where the cause is written
Check the following part in the main body of the email and identify the cause based on Cause for each case.
● The text following "The mail system".
or
● The text following "The following addresses had permanent fatal errors"
Example: If it is “The mail system”
------------------------------------------------------------------------
This is the mail system at host mail**.asahi-net.or.jp.
I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can delete your own text from the attached returned message.
The mail system
<******@asahinet.jp>: host
sbmx.asahi-net.or.jp[202.224.39.235] said: 550 5.7.1
<******@asahinet.jp>: Recipient address rejected: Unknown user (in reply to RCPT TO command)
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■Cause for each case
●User unknown
●User not found
●Invalid User
These are cases where the mail was delivered to the recipient host, but the applicable user (mail address) was not found. Check if the email address of the recipient is correct.
Also, if this happens when you reply to a received email, the sender’s email address (or reply address) may be wrong.
●Host unknown
●Host not found
These are cases where the sender host could not find the recipient host.
Please check the host address of the recipient’s email address (e.g., the part after the @. If the sender is Asahi Net, the host address is @asahinet.jp).
In another case, there may be a failure in the sender or recipient host.
●The user(s) account is temporarily over quota
●Message size exceeds fixed maximum message size
●exceeded storage allocation
These are cases where the sent email volume is too large, or the recipient’s mailbox has exceeded the limit. Check the recipient’s volume limit or reduce the size of your attachment accordingly.
●Cannot send message for xx days(weeks)
●Unable to deliver mail
These are cases where the outgoing mail host server has been sending the mail for xx days (or weeks), but the recipient’s host server did not receive the mail.
Check if there is no failure or congestion in the recipient’s server. There is also a case where the recipient’s server does not exist.