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SMTP Email Error 504 5.7.4 - How to Resolve [SOLVED]

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    Simple Mail Transfer Protocol is the foundation of email communication, providing the framework for sending and receiving messages worldwide on various networks. SMTP supports messaging for both personal and professional communications, upholding the bulk of information updates in a typical day.

    However, the errors in SMTP, including Error 504 5.7.4, significantly mitigate this flow. These errors prevent real-time communication and can also result in business disruptions such as delays and misinterpretations. To sustain the continuous and efficient flow of email, it is vital to identify and correct these errors as soon as possible.

    What is SMTP Email Error 504 5.7.4

    A specific error code inside the SMTP protocol, SMTP Email Error 504 5.7.4, denotes problems with the authentication procedure during email delivery. This error usually appears when authentication processes are either improperly configured or unsupported, which prevents the SMTP server from processing an email.

    Display of the Error

    Those who experience this error will see notifications that specifically mention issues with authentication. Typical instances consist of:

    • The error message “504 5.7.4 Unrecognized authentication type” indicates that the email client’s attempted authentication mechanism is not supported or recognized by the SMTP server.
    • The error “504 5.7.4 Authentication mechanism is too weak” may arise when the server demands a more secure authentication method than what is currently being used.
    • Similarly, the error “504 5.7.4 Command parameter not implemented” may sometimes be associated with authentication command parameters that the server is unable to process.

    The SMTP email error 504 5.7.4 frequently occurs

    1. Authentication Failures

    Unsupported Authentication Method

    The client is unlikely to be using an authentication mechanism that isn’t supported by the server. A more plausible explanation is that there is a mismatch in security settings somewhere – you might have tried to use a very modern and secure method of authentication that the server doesn’t recognize or wasn’t set up to deal with.

    Incorrect Authentication Settings

    If the authentication settings on the server or client’s side are configured incorrectly, this error might arise. This isn’t just about typing the wrong username and password. It may take a more complicated form, such as the configuration of security tokens or key files that haven’t been done properly.

    2. Configuration Errors

    Server Configuration

    The email server might be misconfigured, including any components that would cause it to not recognize or allow the authentication mechanism requested by the client. This could include relevant settings in the SMTP server that should be disabled or enabled, such as security protocols or authentication methods . The email client itself could similarly be incorrect

    Client Configuration

    Therefore, the solution could be intent on forcing the client to use a type of authentication which the server does not support, or it might not have been configured to match the server’s required security settings.

    Protocol Mismatches

    There might be protocol mismatches between the types of SMTP or any other supporting protocol the client and server used. This could lead to misunderstandings regarding the type of authentication wanted.

    3. Server Limitations

    Outdated Server Software

    When more contemporary clients try to connect using settings that the server is unable to handle, they may see this error because the server software is out of date and does not support the more recent authentication methods.

    Restrictive Server Policies

    The usage of specific authentication techniques may be prohibited by the stringent security standards of some servers. Certain servers, for instance, might only accept encrypted passwords and reject requests that try to use a less secure technique.

    Detailed solutions for popular email clients


    • To access the settings, log in to your Gmail account, select “See all settings” from the gear icon.
    • Accounts and Import. From the ‘Accounts and Import’ menu, select the ‘Send mail as’ column. ‘Add another email address’ will be clicked.
    • Enter the following data. Put your name and the email address you want to send from in the popup box. If you would like to administer this account using your primary Gmail account, make sure that ‘Treat as an alias’ is ticked.
    • SMTP Settings:

      • SMTP Server: Enter smtp.gmail.com.
      • Username: Your full Gmail address (including @gmail.com).
      • Password: Your Gmail password. If you have 2-Step Verification enabled, you need to generate an app-specific password.
      • Port: Use 465 for SSL or 587 for TLS.
    • Verify that “Secured connection using TLS” or “Secured connection using SSL” is selected for authentication.
    • Conserve Modifications. Select ‘Add Account’ and adhere to the instructions to verify the email address via a verification email.


    • Access the Account Settings. Navigate to File > Account Settings > Manage Profiles after opening Outlook.
    • Email Accounts. Select “Email Accounts” from the Mail Setup box.
    • Change Account. Click “Change” after selecting your email account. Check the Outgoing Mail Server (SMTP) under “Server Information.” It should be configured in accordance with your email provider (for example, smtp-mail.outlook.com for Outlook).
    • Additional Settings. Select the “Outgoing Server” tab by clicking on “More Settings.” Check the box next to “My outgoing server (SMTP) requires authentication.”
    • Tab Advanced. Select the ‘Advanced’ tab. Use port 587 for SMTP and choose “TLS” for the kind of encrypted connection.
    • Alright, and Next. After selecting “Next” to allow Outlook to test your settings, click “OK” to close the More Settings window.
    • Finish. Click “Finish” and restart Outlook when the test has been successful.


    • Account Security. Visit Yahoo Mail, log in, and proceed to your account details. Click on “Account Security.”
    • Create App Password. If two-factor authentication is enabled, you might need to create an app-specific password in order to utilize it in your email client rather than your main password.
    • Configure Email Client:

      • SMTP Server: smtp.mail.yahoo.com.
      • Port: Use 465 with SSL or 587 with TLS.
      • Username: Your full Yahoo email address.
      • Password: The app password you generated, or your regular password if you don’t have two-factor authentication enabled.
    • Save Settings. Ensure your email client uses these settings and re-test sending an email.

    Other Clients

    • Verify SMTP Settings. To determine the proper SMTP settings, including server address, port, and whether SSL/TLS is required, consult the documentation for your particular email platform.
    • Verify Authentication. Make sure the email client is set up for authentication and that the username and password you are using are accurate (usually your entire email address).
    • Update or Reinstall. Updating the email client to the most recent version or reinstalling it may help fix configuration issues if problems continue.
    • Contact Support. To make sure your settings are accurate and accepted by the server, contact the support staff of your email provider if the error persists.

    Benefits of using email warm-up services

    Dashboard Warmy

    Email warm-up services like Warmy.io can enhance your email sending practices by slowly increasing the number of emails sent from any new or underused email account. This will help you avoid SMTP errors and keep a good sender reputation.

    Properly warmed-up accounts are unlikely to be flagged by email service providers for suspicious activity, which can cause such SMTP errors as the one explained above. Warmy.io lets you not only do the warming process but also provides other tools that help with email deliverability. It offers free email deliverability tests that allow you to test your emails and see if everything is working fine before you start any campaign to avoid any related issues.

    Moreover, the service runs blacklist checks to make sure your email has not been flagged by any anti-spam databases. Last but not least, it provides a fancy tool to generate SPF and DMARC records. These records are needed for email authentication and email protection as they allow controlling the email that claims to be sent from your domain. All these features make Warmy.io an all-in tool for managing email and ensuring it reaches your recipient.

    SPF generator


    Thus, to eliminate the SMTP Email Error 504 5.7.4, one should closely delve into the email authentication methods’ peculiarities and make sure that both the email server and client are configured correctly to get access to supported protocols. Irrespective of whether you deal with your emails through Gmail, Outlook, or Yahoo, or through various less-known platforms, you must align SMTP settings with server capacities and security standards.

    With the help of Warmy.io, it is much easier to increase email sending outcomes since it allows users to warm up their email accounts in the right way, to run deliverability tests, and to have a strong sender reputation. These steps will help avoid common SMTP error-related issues and make emails an effective communication tool that quickly reaches recipients.

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