Sender Address Rejected [Postfix]


We have just finished setting up Mailinabox but we are having issues with the @Alias management.
Basically, if we have an alias that is linked to an external domain (gmail for example), the user receives the error "SMTP ERROR (553): Failed to add recipient “recipient-email-address” (5.7.1 <_sender-email-address>: Sender address rejected: not owned by sender-email-address

In order to quick fix it, we modified the postif/ and removed “reject_authenticated_sender_login_mismatch” from the line “smtpd_sender_restrictions=reject_non_fqdn_sender,reject_unknown_sender_domain,reject_authenticated_sender_login_mismatch,reject_rhsbl_sender”.

Any idea how to sort it out more properly?

Thanks in advance,

Please be more specific.

Hi Josh,

Thanks for your fast reply.

A few more points:

  • The error (SMTP ERROR ‘553’) is mentioned on roundcube when the user tries to send an email;
  • The Alias is created through the /admin section and is for example: TO
  • If we remove the Alias, the problem disappears

Hope that it helps,

Oh I see. Don’t use an alias for the same address you have a user account for. We won’t allow that in the future. Instead, use a mail filter within roundcube.

I can see that this is a bit of a hackerish way to do things, but it is something that I use at the moment.

Currently my other half uses Gmail with an email address managed by MIAB. I forward all the email to her Gmail address and she sends from the MIAB email address. She needs a full email account to send from MIAB via SMTP (unless I’m mistaken), but forwarding the email to her (rather than relying on Gmail polling her account) means she gets messages much quicker.