Server Error 503 - server requires authentication

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Joined: Thu Apr 20, 2006 12:25 pm

Server Error 503 - server requires authentication

Post by » Thu Apr 20, 2006 12:35 pm

Ive been authenticating clients for sometime, but after applying the lastest MS patches, mail clients see this message:

The message could not be sent because one of the recipients was rejected by the server. The rejected address was "", Subject: zzzz, Account: <server address> Protocol: SMTP, Server Response: '503 This mail server requires authentication when attempting to send to a non-local e-mail address.... Error Number: 0x800ccc79

Multiple clients are getting this message, and no one can send mail. Receiving mail still works ok (Clients authenticate both ways). Ive uninstalled the MS patches, changed authentication passwords, and upgraded MailEnable to 1.95 with no luck. The clients have made no changes to their configs - the only change was the MS patches.

Any help is appreciated.

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Joined: Tue Dec 06, 2005 8:32 am

Post by SoHoAlex » Mon Apr 24, 2006 9:33 am

"this server requires authentication", enable this in the mailclient and it's all good to go.

depending on your server's configuration you might have setup 'pop before SMTP authentication', so customers who have checked their e-mail before sending out new ones wont get the message

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Joined: Mon May 22, 2006 4:30 pm

Post by KjeldB » Mon May 22, 2006 4:32 pm


I have the exact same problem, but with forward mails. Does anybody have a hint, what to do here about the authentication problem?
Best regards,
Kjeld B.

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Joined: Thu Dec 09, 2004 7:09 pm

Post by zeusdk » Mon Jul 23, 2007 12:13 pm

Me too, same problem here, also redirecting e-mails.

What to do?

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Joined: Thu Dec 09, 2004 7:09 pm

Post by zeusdk » Mon Jul 23, 2007 1:33 pm

Ahhhh, the IME_ADMIN did not have read primission in the reg db on our very new 64 bit 2003 server (HKEY_LOCAL_MACHINE->SOFTWARE->Wow6432Node->Mail Enable->Mail Enable) and the domain was missing in the domains folder in the GUI.

The first must be a bug in the 64 bit version of Mail Enable and the last was me forgetting to set up the post office correctly.

It is working now.

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