Warmy Blog

SMTP Email Error 454 - How to Resolve [SOLVED]

Talk with a deliverability expert!

No need to flee, it’s totally free


    Emails are the backbone of modern communication, especially in the business world. They zip through the internet, reaching out across the globe in seconds, thanks to the Simple Mail Transfer Protocol, or SMTP for short. SMTP is like the postal service of the internet—it makes sure your emails get where they need to go. But just like real mail can hit snags, so can your emails. Enter SMTP Error 454, a hiccup on the email highway that stops your messages in their tracks, affecting how quickly and reliably they reach their destination.

    In this friendly guide, we’re diving into the world of SMTP Error 454, showing you exactly what it is and why it matters. Think of it as a “return to sender” notice for your digital messages. When this error pops up, it means there’s a temporary roadblock preventing your emails from being delivered, which can be a real headache if you’re trying to communicate quickly and effectively. Let’s unpack what causes this error and how you can fix it, ensuring your emails always find their way to the right inbox.

    Deciphering SMTP Error 454

    Think of sending an email as mailing a letter, only to have it returned with a note: “Can’t confirm it’s you, so we can’t deliver this.” That’s SMTP Error 454 for you—a hiccup where your email server can’t quite place who you are, pausing your email’s journey.

    The standout feature of SMTP Error 454 is its laser focus on authentication. Unlike other errors that may block your email’s path for reasons like wrong addresses (SMTP Error 550) or an overwhelmed server (SMTP Error 421), Error 454 zooms in on identity verification. Imagine holding the correct key, yet the lock won’t turn. The server encounters a snag in confirming your identity and needs a bit more to proceed with delivery.

    This authentication hiccup signals it’s time for a solution-focused approach: verifying your credentials are up-to-date, ensuring your email settings are aligned with server requirements, or waiting out temporary server glitches. Addressing these points can smooth out the bumps, clearing the way for your emails to reach their destination without a hitch.

    Root causes of SMTP error 454

    Verify Your Credentials

    The essence of SMTP Error 454 often boils down to incorrect login details. Regularly updating and verifying your email client’s credentials can swiftly resolve this issue, ensuring smooth access to email delivery.

    Align with Server Updates

    Email servers periodically enhance their security or undergo software upgrades. Keeping your email client in sync with these updates eliminates compatibility issues, effectively clearing this roadblock.

    Embrace Two-Factor Authentication (2FA)

    As email services bolster security with 2FA, ensuring your setup accommodates this extra security layer can prevent Error 454. Adapting to these security measures not only enhances protection but also smoothens your email transactions.

    Tackle Temporary Server Downtime

    Sometimes, the server itself is momentarily out of service, be it for maintenance, overloads, or unplanned outages. Patience is key here—waiting out these periods often means Error 454 resolves on its own.

    Service-Specific Strategies

    • For Gmail Users. Google’s security measures against less secure apps may trigger Error 454. Ensuring your email client meets Google’s security standards can mitigate this issue, affirming your identity to Gmail’s servers.

    • For Outlook Users. Microsoft Outlook may flag Error 454 during its upgrade phases or if there’s a disconnect in security settings. Matching your email client’s configuration with Outlook’s updated requirements ensures uninterrupted email flow.

    • For Yahoo Users. Yahoo Mail’s vigilance against unusual access attempts can result in Error 454. Regularly confirming your access methods align with Yahoo’s security protocols can help avoid this authentication hiccup.

    Fixing SMTP error 454: email platform solutions

    Overcoming SMTP Error 454 is key to uninterrupted email communication. Follow these direct, platform-specific solutions for Gmail, Outlook, Yahoo, and beyond to quickly get your email back on track.

    For Gmail Users

    Enable Less Secure Apps (if necessary)

    In Google Account settings, under Security, allow access for less secure apps.

    Update and Verify

    Ensure your password is current and 2FA settings are correctly configured, possibly requiring an app-specific password.

    Correct IMAP/SMTP

    Adjusting your email client’s IMAP and SMTP settings according to Gmail’s guidelines is crucial for ensuring smooth email operation and resolving SMTP Error 454. Here’s how to do it step by step.

    ✅ IMAP Settings for Gmail
    1. Enable IMAP in Gmail. First, log into your Gmail account. Click on the gear icon to open Settings, then go to ‘See all settings’. Navigate to the ‘Forwarding and POP/IMAP’ tab and ensure IMAP is enabled.

    2. Configure Your Email Client. Open the settings or account preferences in your email client. Locate the section for adding or editing an IMAP account.

    3. Enter IMAP Server Details:

      • IMAP server: imap.gmail.com
      • Port: 993
      • Require SSL: Yes, choose SSL or TLS as the encryption method, depending on your email client’s terminology.
    4. Authentication. Input your full Gmail address as the username (including @gmail.com) and your password. If you use 2FA, you’ll need to generate and use an app-specific password.

    ✅ SMTP Settings for Gmail
    1. Access SMTP Settings. In the same section where you edited your IMAP settings, look for SMTP settings. This is usually in the account settings where you can add or edit an email account.

    2. Enter SMTP Server Details:

      • SMTP server: smtp.gmail.com
      • Port: 587 (for TLS/STARTTLS) or 465 (for SSL)
      • Require SSL/TLS: Yes, select TLS or STARTTLS, or SSL if using port 465.
    3. Authentication Required. Make sure to enable authentication with your full Gmail email address as the username and your password. Again, for 2FA users, an app-specific password is necessary.

    ✅ Finalizing Settings
    • Save and Test. After entering all details, save your changes. Most email clients offer a way to test the settings. Use this feature to ensure everything is correctly set up. If the test fails, double-check all the information you entered.

    • Common Troubleshooting.If you encounter issues, ensure that you have correctly enabled IMAP in your Gmail settings and that you are using the right password or app-specific password for 2FA. Also, verify that your internet connection is stable.

    For Outlook Users

    Updating Server Settings in Outlook

    1. Access Account Settings. Open Outlook and click on the ‘File’ tab at the top left. Under Account Information, click on ‘Account Settings’ and then select ‘Account Settings’ from the dropdown menu.

    2. Edit Email Account. In the Email tab, find your account and click on it, then select ‘Change…’ to access the settings.

    3. Server Settings Update:

      • Incoming mail server (IMAP). Ensure it’s set to outlook.office365.com for an Outlook.com account, or check with your IT department for a corporate account.
      • Outgoing mail server (SMTP). This should be smtp.office365.com for Outlook.com accounts.
      • Port Settings. IMAP should be set to 993 with SSL encryption, and SMTP should be 587 with TLS encryption.
      • Username and Password. Your full email address and current password go here. Remember, your username is usually your email address.
    4. More Settings. Click ‘More Settings…’, go to the ‘Outgoing Server’ tab, and ensure ‘My outgoing server (SMTP) requires authentication’ is checked. In the ‘Advanced’ tab, confirm port and encryption settings as previously noted.

    5. Save Changes. Click ‘OK’ to close the ‘More Settings’ window, then click ‘Next’ on the change account window. Outlook will test the settings. If everything is correct, click ‘Finish’.

    Refreshing Your Password

    Regularly changing your password is vital for security. If you’ve changed your password online, you need to update it in Outlook. Go to the account settings as described above, select your account, click ‘Change…’, and update your password in the provided field.

    Enabling Modern Authentication

    1. What is Modern Authentication? Modern Authentication is a more secure method to access your Outlook account, using Two-Factor Authentication (2FA) and other verification methods beyond just a password.

    2. Check if Available. Modern Authentication is enabled by default in Outlook 2016 and later. If you’re using an older version, or if your organization controls these settings, you might need to check with your IT department to enable Modern Authentication.

    3. Activate 2FA. For the best security, enable 2FA on your Microsoft account through the Microsoft security settings page online. Once 2FA is enabled, you may need to use an app password in Outlook, which you can generate on the Microsoft account security webpage.

    For Outlook Users

    Securing Your Yahoo Account

    1. Access Security Settings. Log into your Yahoo account and navigate to the “Account Security” page. This can typically be found in the account settings or profile section.

    2. Enable Permissions. Look for a setting that controls permissions for less secure apps or access by third-party email clients. Yahoo periodically updates its security features, so the exact name might vary. If you use a third-party email client, you may need to allow access for these apps to ensure seamless email sending and receiving.

    Utilizing App Passwords with 2FA

    1. Activate 2FA. On the “Account Security” page, find and enable Two-Factor Authentication. You’ll be prompted to add a phone number or backup email address for verification purposes.
    2. Generate App Password. Once 2FA is activated, you’ll see an option to generate app passwords. Select this option and follow the prompts to create a unique password for your email client. This password will be used instead of your account password in the email client settings.

    Configuring SMTP and IMAP Settings for Yahoo Mail

    1. IMAP Settings:

      • Server: imap.mail.yahoo.com
      • Port: 993
      • Encryption: SSL/TLS
      • Username: Your full Yahoo email address
      • Password: Your Yahoo account password or the app password if 2FA is enabled
    2. SMTP Settings:

      • Server: smtp.mail.yahoo.com
      • Port: 465 (for SSL) or 587 (for TLS/STARTTLS)
      • Encryption: Choose SSL for port 465 or TLS/STARTTLS for port 587
      • Username: Your full Yahoo email address
      • Password: Use your Yahoo account password or the app password generated for 2FA

    Implementing the Settings

    1. Update Email Client. With these settings noted, open your email client and locate the account settings or preferences section. Update both the incoming (IMAP) and outgoing (SMTP) server settings with the details provided above.
    2. Authentication Details. Ensure you enter your full Yahoo email address as the username. For the password, use the specific app password you generated if 2FA is enabled.
    3. Save and Test. After adjusting the settings, save your changes. Most email clients offer a function to test these settings. Use it to confirm everything is configured correctly. Successful tests should mean you’re all set to send and receive emails without facing SMTP Error 454.

    Navigating through variants of SMTP error 454

    Each variant of SMTP Error 454 signals a specific issue. Here’s how to tackle them efficiently:

    454 4.7.1: Permission Denied

    • Check and adhere to email sending limits.
    • Ensure your IP isn’t blacklisted.
    • Adjust overly strict server policies if you manage your server.

    454 4.7.0: Temporary Authentication Failure

    • Re-confirm your email client’s login credentials.
    • For services like Gmail, enable access for less secure apps or configure 2FA properly.
    • Wait a bit before retrying, as the issue might resolve itself.

    454 4.3.0: Temporary Service Failure

    • Check the email service’s status for any known issues.
    • Pause before sending emails again, allowing time for server recovery.
    • Use webmail or another account for urgent emails until the service stabilizes.

    454 4.7.5: Cryptographic Failure

    • Update your email client to support the latest encryption standards.
    • Ensure the server’s encryption settings are correctly configured.
    • Contact your email provider if you’re not managing the server for support on secure connections.

    These targeted actions can help you swiftly address and solve different SMTP Error 454 scenarios, keeping your email communications flowing smoothly.

    Boosting email deliverability with warm-up services

    email deliverability

    Warm-up services are essential for anyone looking to boost email deliverability and maintain a strong sender reputation. Here’s how leveraging these services, especially Warmy.io, can significantly mitigate issues like SMTP Error 454 and enhance your email strategy:

    • Builds Reputation. Gradually increase sending volumes to establish you as a trustworthy sender, reducing the risk of being flagged by ISPs.
    • Boosts Inbox Placement. A solid reputation means your emails are more likely to be welcomed into inboxes, steering clear of spam folders.
    • Reduces Errors. Avoid sudden spikes in email volume that can trigger SMTP errors, ensuring smoother email campaigns.
    • Warmy.io Advantage. Offers personalized warm-up plans and automates interactions to improve your sender score. It provides valuable analytics for optimizing your email strategy and directly tackles SMTP Error 454 by reinforcing your email’s legitimacy and deliverability.

    Invest in Warmy.io to not just solve SMTP Error 454, but also to secure a future where your emails consistently reach their intended destination.


    In this guide, we’ve broken down SMTP Error 454, offering straightforward solutions for common causes and detailing how to adjust settings across Gmail, Outlook, and Yahoo. We’ve also introduced Warmy.io, an essential tool for boosting email deliverability and sidestepping SMTP Error 454 by building a solid sender reputation.

    Take these insights as your toolkit for tackling SMTP Error 454 efficiently. By applying the suggested adjustments and considering the support of warm-up services like Warmy.io, you’re setting the stage for more successful, uninterrupted email communication. Remember, addressing SMTP Error 454 isn’t just about fixing a problem—it’s about optimizing your email strategy for the long haul.

    Scroll to Top