Diagnosing Mail Problems
If you suspect a mail problem, please diagnose it using the hints below.
Mail sent from a2i to a remote site
- Suppose mail sent from a2i does not reach a remote site, and does
not bounce. Usually mail that cannot be transferred to a remote site
will remain queued for two or three days before bouncing back. The mail
queues at a2i reside on several machines, and not all machines that
handle mail allow user logins. So you will find it hard to figure out
if the outgoing message is in a mail queue. Send a second message to
the same address, wait a few hours, and then if neither the first nor
the second message has either reached or bounced back, let
email@example.com know. (You might need to telephone the recipient to
check if the email reached.)
- Another way of figuring out whether the mail reached the remote
site or not is to deliberately send mail to an invalid address at
the same site. For example, if you previously sent mail to
firstname.lastname@example.org, send another message to
a made-up address at the same host:
email@example.com. If this message
bounces back to you quickly, this tells you that your original
message probably reached the remote site. (If it didn't,
it would have bounced back to you by now.)
- Suppose mail sent from a2i to a remote site bounces back. Look in
the bounced message carefully. It will usually tell you why the message
bounced. The five most common reasons are given below, and the bounce
message will usually let you distinguish between them.
Although the errors listed above are the most common, other errors can
also occur, leading to mysterious error messages. In all cases try
waiting a few hours and sending your message again.
- Bad domain name: Perhaps you are sending to an email address
in which the portion of the address to the right of the @ sign is
not valid. Error messages seen will be similar to:
'host unknown' and 'never heard of host xxx'.
- Bad local part: Perhaps the portion to the left
of the @ sign in the destination address
is not valid, e.g., the user does not exist at the
remote site. Error messages will be similar to:
'no such user', 'user unknown'.
- Bad sending address: Otherwise, perhaps the reply address
you are using in outgoing mail is bad. Some sites will refuse to
accept mail that shows a bad reply address. Error messages will
be similar to: 'cannot route to sender', 'domain must resolve'.
(NOTE: In this case it's also possible that the bounced message will
never get back to you.)
- Recipient's mailbox is full or disk quota is exceeded. Wait
a day or two and try again. Error messages will be similar to
'mailbox full', 'disk quota exceeded'.
- Bad software configuration at the remote site. Error messages
will be similar to 'error 0', 'service unavailable',
'permission denied', 'mail loops back to myself',
'configuration error', 'I refuse to talk to myself'.
Mail sent from a remote site to an a2i user
The causes will be similar to those listed above, except that the
direction of the mail is different. Where the above hints ask you to
contact firstname.lastname@example.org, the sender should contact his own service
Who makes the diagnosis?
- Problem sending from a2i to a remote site: Diagnosis will be made
by you or by a2i support staff.
- Problem sending from remote site to a2i: Diagnosis will be made by
remote sender or by remote sender's service provider. Diagnosis will
generally not be made by a2i support staff in such cases, unless the
remote service provider investigates first and then contacts us for
to a2i communications home page
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