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Mail Delivery Subsystem - Message could not be delivered

Email messages may be returned to you as undeliverable for several reasons, many of which can be easily corrected. Please note that you do not need to respond to the messages returned to you.

The following are some of the reasons why a message may be returned to you:

  • You may have typed the incorrect email address. If you are typing the correct email address, try contacting your recipient by phone or in person to verify that you have his or her correct email address.

  • If the email address is correct, there may be a temporary mail delivery problem on your recipient's system. You can try contacting your recipient to find out if he or she is experiencing problems receiving email. If your email message is returned to you with the comment "User unknown, " then that email address is invalid. The email address may be invalid for a number of reasons: it may never have existed, the subscriber may have changed his or her account name or email service, or you may have mistyped the address.

  • If you sent a message to a NetZero member and it is returned with the message "Mail quota exceeded," then this NetZero member's mailbox is full or the account is inactive:

    • A "full mailbox" means that this member has reached the limit for how much mail he or she can store on NetZero's central computers.

    • An "inactive account" means that that this member has not used his or her account for at least 60 days. When an account is inactive, any mail that has not been picked up in at least 60 days is deleted and any new mail is returned to its sender. Unfortunately, deleted mail cannot be restored.

    In both cases, try to contact this person and let them know that they need to check their NetZero mail. Once they do this, you'll be able to send email messages to this person.

  • Look at the message headers of the message returned to you. If they contain any of the following comments, then your recipient's Internet Service Provider or other domain is rejecting messages sent by NetZero members:

    • "This domain is banned"
    • "This domain is banned for spamming"
    • "Message from domain rejected"
    • "Access denied"
    • "Service unavailable"
    • "Unsolicited email is refused"

    Blocks of this sort are rare, but occasionally occur, usually due to a misunderstanding of NetZero's strict policies against spam.

NetZero's Security and Abuse department works to have these bans lifted. To notify them of a domain ban, please forward the message that was returned to you, including the message's full headers to and type "domain ban" in the Subject line of the message. You should also encourage your friends with accounts at this service to tell the service's postmaster that they want to receive mail from NetZero.

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