Authentication failure when forwarding email

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Joined: Wed Jul 28, 2021 4:37 pm

Authentication failure when forwarding email

Post by B@IATech » Wed Jul 28, 2021 4:46 pm

I have a post office that, when a user forwards an email to another user in the same domain, they keep getting the following:
This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
host []
SMTP error from remote mail server after MAIL FROM:<> SIZE=3734:
551 This mail server requires authentication before sending mail from a locally hosted domain. Please reconfigure your mail client to authenticate before sending mail.
I am not sure what setting I have wrong and I can't seem to hunt down an answer when searching online and in the forums here. Anyone have any ideas for me?

Emails created new and sent do not have an issue, only if it is forwarded.

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Posts: 9545
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Location: Melbourne, Victoria, Australia

Re: Authentication failure when forwarding email

Post by MailEnable-Ian » Thu Jul 29, 2021 1:04 am


Look within the 551 error section.

Ian Margarone
MailEnable Support

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