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Problem sending to multiple users when one user is not valid

Posted: 2007-09-06 15:35
by Dragwyr
I tried a search for this, but did not find anything. I need to know if there is a setting or fix for a situation we ran into yesterday.

The situation:
A user sends to a large group of users she has setup in her mail client. She then gets a message back saying "Unknown user", and the message does not go through to anyone.

What is happening is if someone with an hMs account sends to a group and one address in the group is wrong, AND the wrong address is addressed to somone on our hMs, the whole message does not get delivered.

I have a hMs setup with the domain ""

I send from my e-mail address, "" and send to 100 people, some have external accounts and some have accounts on my "", but I spell one of the accounts wrong, or it is not on our server (Lets say I send to "" and that account is NOT created on my server.).

The server log shows the following:
"SMTPD" 1940 1341 "2007-09-06 09:22:52.906" "" "SENT: 550 Unknown user"

And the message does not send to anyone I was sending to.

Any ideas on how to fix this? Shouldn't it send to everyone it can and just send a message back to the sender saying which addresses were not found? Or something like that?

Posted: 2007-09-06 16:10
by ^DooM^
What version of hmail are you running? I am sure this has been reported before.

Posted: 2007-09-06 16:37
by iprat

I am astonished, but my hMailserver does this (see signature for version number).

I send a message to and, and the message is bounced by the email client querying me to correct the adress. I am given the oportunity to correct the error as I use Thunderbird 2.0, but maybe another email client doesn't.

Anyway the message error is noticed, it is not silently rejected, maybe you are using an automated program to send this ? (wich doesn't listen to server's answer).

Posted: 2007-09-06 20:08
by martin
It's up to the email client wheter delivery should be cancelled or not when a single recipient fails. This decision is taken by the email client - not by the email server.

Posted: 2007-09-07 14:10
by Dragwyr
I'm running v 4.4 b270 on a Win 2k3 Server.

The person who had the problem was using the Netscape Mail Client and there was no option to cancel the delivery. There was no automated program to send the message out. It was a group that was defined in Netscape Mail that had about 75 e-mail addresses in it. One of them happened to be wrong that was sent to our server here.

This is also happening in Thunderbird. The error I get is, "An error occured while sending mail. The mail server responded: Unknown user. Please verify your email address is correct in your mail preferences and try again." It shows only an "Ok" button and that is it. The message does not deliver to any of the valid e-mail addresses on our server and the message is completely dropped by the server. When the invalid address is removed from the list on the client, it delivers.

Understand that this is only happening when someone with an e-mail account on our server is sending to a non-existent account on our server. This does not happen when sending to a non-existent account on an external email server.

Posted: 2007-09-07 18:27
by martin
The decision to cancel the mail delivery is taken by the email client - not the email server. hMailServer just tells the email client that one of the recipients was invalid. And after that, your email clients decides to quit the delivery. There's nothing hMailServer as an email server can do to prevent this since it's the email client that decides to give up..

Posted: 2007-09-11 14:01
by Dragwyr
Thanks for your reply, Martin. The way you explain it makes perfect sense.