Easy Way To Fix SMTP Error 551: Relay Denied

Here are some simple methods that can help you resolve your relay rejection issue due to SMTP 551 error.


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    This confusion arises when “SMTP Authentication SMTP Authentication SMTP Authentication, often abbreviated as SMTP AUTH, is an extension of the SMTP protocol” that a client can connect to, with an authentication mechanism supported by the server to use. It is primarily used on dispatch servers that require authentication. https://en.wikipedia.org ›wiki› SMTP_Authentication SMTP – Wikipedia Authentication is not enabled in your email client. The solution is to configure your email client to use SMTP authentication. In Outlook, you must enable the “My server uses authentication” option in the “Outgoing mail server” clause to enable authentication.

    Email error 551 is a signal that counts when trying to deliver to an email server that is not processing emails for the recipient.

    You should receive a messageServer bounce message with various 551 email errors in the subject line, and the body should contain the original text you were trying to deliver.

    Example Bounce Message

    Common Variants Of

  • Error 551
  • . email 551

      5.1.1 The recipient does not actually

    • 551 exist
    • 5.1.1 The user definitely exists

    • 551 IVF denied
    • 551 is definitely not our client
    • 551 [e-mail is being protected] did not work for forwarding the address
    • 551 < [e-mail is being protected] > … User not local
    • 551 Relay detection denied
    • 551 Not all relay hosts – mail must be sent to or from a domain host.
    • 551 Unknown user.
    • 551 users are not being held. The repeater requires authentication.
    • 551 non-local users; Please try

    Eliminating The Perfect 551 Email Error Rejection

    Return path: <>
    envelope to: [secure email address]
    delivery date: Thursday, 25 October 2012 11:19:59 from -0700
    Received: biz100. inmotionhosting.com mailnull with national (Exim 4.77) id 1TRS2B-00033h-Fn
    for [secure email] ; Thu, October 50, 2012 11:19:59 AM -0700 – Recipient with error X: [email protected]
    Sent automatically: automatic reply
    By: Mail delivery system << a> [Email secure] >
    To: [Email secure]
    Subject: Email Delivery Error: Return Sender
    Message ID: From << a> [email protected] >
    Date: October 25, 11:19:59 -0700

    The message you sent might not have been delivered to one or more recipients
    . This is a serious and persistent mistake. Failed to execute the following address (s):

    smtp error 551 relay denied

    – – – This is a copy of this message, including all headers. – –

    [Secure Email] [Secure Email] [Secure Email] [Secure Email]

    The 551 error bar should usually be a hard bounce. For a closer look at the difference between soft and hard bounces and most reasons for bounced emailsSee Why Email Bounces, Bounces, and Errors?

    In the above failback example, you can see that the reason for the message to fail is definitely because the RemoteDomains.com server has no control over the email address. mail from [email-protected] to your email address.

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    The smpt error in Exchange 2007 ‘smtp; 551 5.7.1 Relay prohibited ”In the case of incoming e-mails, the sender receives this error when trying to send a positive message to the alternate domain. This is definitely a one-time Exchange Server installation.

    What does server Error 550 relay not permitted mean?

    When a user receives a 550 “Navigation Not Allowed” error, it means they are not allowed to send a specific email through the server from which some people are trying to send an email. Typically, when users send mail from their Internet Service Provider (ISP) mail servers, they do not need to be authenticated.

    # 1 We have added a new policy for new innovative domains and also added domain replacement to my default policy. (The result is the same whether it is in the default directive and sometimes not)

    # 2 I also set up a new domain Website as an accepted and authoritative domain.

    # 3 The mailbox I need to send consists of a new domain email address, and the address follows the conventions chosen by the policy.

    # 4 I usually have an MX record in DNS and I validate it with MXToolbox on the internet.

    # 5 Can I telnet to the new mx domain on the internet on port 25 and the SMTP banner will display as expected. The end result banner and banner are the same in Telnet to be the main domain.

    smtp error 551 relay denied

    When I post items to a domain from the main exchange domain, the mail goes through. If I answer, it works too.

    How do I fix Outlook 550 relay not permitted?

    Read the best visual step-by-step troubleshooting guide for this particular email client.Follow the settings that can access the outgoing SMTP server.Select the displayed option to require password authentication.Use the same username and password for the inbound and outbound server.

    What positioning am I missing here? I need Exchange To 2007 to accept incoming email from the Internet.

    This one hit me now. I read the documentation


    But an email generated with the ASP / ASP.NET desktop application throws error 551.

    What does Relay Access Denied mean?

    Denied inaccess to a repeater is a rather serious drawback. This indicates that the server should not allow sending e-mail messages to another mail server. The most common causes are the following errors: the sender did not check the outgoing mail server, there are still incorrect configurations.

    What has been tried is the relay settings in the SMTP parts with:

    • Allow relaying for outauthenticated senders enabled and disabled (if enabled, using your own specially added Windows account with user rights and IIS_IUSRS)
    • Allow Forwarding for Good IPs (with 2 Server IPs and
    • Allow forwarding of local sender addresses (enabled)
    • POP before SMPT check (enabled and disabled)

    In addition, all security settings on the user’s SMTP Security tab have been removed.

    Otherwise, the mail server should be a freebie for spammers.

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