2.24.3.7. Error "553 5.7.1 Sender address rejected: not owned by user"

Error "Sender address rejected: not owned by user"that occurs when sending a letter indicates an attempt to send a letter using someone else's or another mailbox. There are two situations in which this error can occur:

• In case the letter is sent with the indication of another mailbox, but within the same domain.
• If the letter is sent with the indication of a different mailbox using a different domain.

Attention! The error will indicate the mailbox in which the authorization was made, and the mailbox that will be indicated as the sender:

(5.7.1 <admin@example.com>: Sender address rejected: not owned by user mail@example.com)

• admin@example.com — the mailbox in which the authorization was made.
• mail@example.com — the mailbox specified as the sender.

If, when sending a letter, authorization was performed in the mailbox admin@example.com, but as a sender in the header From: the mailbox mail@example.com is specified (with the same domain) and an error occurs — that means in the settings of the domain mail disabled option "Allow sending emails from other users within your domain name".

To solve the problem you need:

• Or, do not specify another mailbox as the sender.
• Or turnon option "Allow sending emails from other users within your domain name".

If, when sending a letter, authorization was performed in the mailbox admin@example.com, but as a sender in the header From: If the mailbox admin@domain.com is specified (with a different domain), then the mailbox with the same domain must be used as the sender. Sending on behalf of a mailbox with a different domain is not possible.