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SMTP Email Error 513, 515, 517 - How to Resolve [SOLVED]

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    Email is still a mainstay of corporate communication in the digital age, supporting everything from everyday operations to major projects. Errors in SMTP (Simple Mail Transfer Protocol) email, however, can interfere with this vital line of communication, causing delays, lost chances, and even harm to reputation. SMTP Email Errors 513, 515, and 517 are especially problematic among these interruptions; they each indicate distinct problems that can have a major negative effect on email transmission.

    Maintaining the accuracy and effectiveness of corporate communications requires quick and efficient resolution of these mistakes. These particular SMTP issues will be examined in this article along with their causes and thorough fixes to guarantee the stability and dependability of your email systems. Companies can protect their email communications from any interruptions and preserve their operational continuity by fixing these mistakes.

    Understanding SMTP email error 513, 515, 517

    Each of the SMTP email errors 513, 515, and 517 poses different difficulties and is usually accompanied by particular error messages that aid in identifying the underlying problems. Identification and resolution of the issues affecting email communication depend on an understanding of these communications.

    SMTP Email Error 513

    Usually, this problem shows up as

    “513 Address type not supported”.

    It happens when the recipient’s email address has a syntax mistake or the email server is unable to parse the address.

    SMTP Email Error 515

     Possible error message for this problem is

    “515 Destination mailbox address invalid”.

    It means that either the recipient’s email address is not getting mails or does not exist on the receiving server. Restrictions on the receiving server, a domain that is no longer operational, or a typo of the email address might all be the cause.

    SMTP Email Error 517

     One may see a notice saying,

    “517 Problem with senders mail attribute, check syntax”.

    This message indicates a problem with the email characteristics of the sender, including the email header format or other configuration settings that don’t match the requirements of the receiving server.

    Users are notified by these error codes when particular problems with the email sending process require quick action. Whatever the issue — address syntax, server setup, or mail properties — each one needs a focused troubleshooting strategy to guarantee that communication is continuous and smooth.

    Understanding the root causes of SMTP email errors 513, 515, and 517

    SMTP Email Errors 513, 515, and 517 can stem from a variety of sources, each related to different aspects of the email sending and receiving process. Understanding these causes is key to diagnosing and fixing the issues effectively. Here’s what typically leads to each of these errors:

    SMTP Email Error 513: This error often arises from

    • Incorrect Email Format. The email address format does not comply with standard email formatting rules. This could be due to missing elements like the “@” symbol or incorrect domain names.
    • Unsupported Address Types. Some servers may not support certain types of email addresses or special configurations, leading to this error when encountering an unfamiliar address type.

    SMTP Email Error 515: Common causes include

    • Non-existent Email Address. If the recipient’s email address is typed incorrectly or if the domain name does not exist, the server will return this error.
    • Server Restrictions. The receiving server may have strict policies regarding which email addresses are considered valid, or it may block emails from certain senders.

    SMTP Email Error 517: This error is generally caused by

    • Improper Email Header Configuration. Errors in the email header, such as syntax mistakes or incomplete information, can lead to this error.
    • Misconfiguration of Sender Attributes. Incorrect settings in the sender’s email client or server, such as SMTP authentication issues or incorrect sender information, can trigger this error.

    Step-by-Step Solutions to Resolve SMTP Email Error 513, 515, 517

    Navigating through Salesforce to check and enhance email deliverability involves a series of steps tailored to different environments within the platform. Here’s how you can ensure your emails are making their mark:

    Resolving SMTP Email Error 513

    • Verify Email Address Format. Double-check the recipient’s email address for any typos or formatting errors. Ensure it includes an ‘@’ symbol and a valid domain.
    • Check for Unsupported Features. Some email services may not support certain special features or address types. Consult your service’s help documentation to ensure compatibility.

    Resolving SMTP Email Error 515

    • Confirm the Recipient Address. Re-enter the recipient’s email address to make sure it is spelled correctly and actually exists. If possible, ask the recipient to confirm their email address.
    • Check Server Restrictions. Contact the administrator of the recipient’s email server to ensure that there are no restrictions preventing your emails from being delivered, such as blocking emails from your domain or IP address.

    Resolving SMTP Email Error 517

    • Inspect Email Headers. Examine the headers of your outgoing emails to ensure they are correctly formatted. This includes verifying that fields like ‘From’, ‘To’, and ‘Subject’ do not contain unusual characters or formatting errors.
    • Authenticate Your Email. Ensure your SMTP settings are correctly configured, especially that you are using the correct username, password, and authentication method required by your email service provider.

    General Troubleshooting Steps

    1. Update Email Client. Ensure that your email software or application is up-to-date, as updates can fix bugs that may be causing these errors.

    2. Review Email Server Settings. For email services like Gmail, Outlook, and Yahoo, ensure you are using the recommended SMTP settings:

      • Gmail: smtp.gmail.com, SSL required, port 465; or TLS required, port 587.
      • Outlook: smtp-mail.outlook.com, TLS required, port 587.
      • Yahoo: smtp.mail.yahoo.com, SSL required, port 465.
    3. Contact Support. If the issue persists, contact the support team for your email service provider. They can provide more detailed guidance based on the specifics of your account and their server configurations.

    spam test

    One of the best ways to help you avoid SMTP Email Errors like 513, 515, and 517—which frequently result from deliverability problems—is to use an email warm-up service like Warmy.io.

    Warmy.io is made to improve your reputation for sending emails generally. Warmy contributes to the good sending reputation of new or reset email accounts by progressively boosting the volume of emails sent from them. For new domains or email addresses that have to establish trust and stay out of spam, this procedure is essential.

    The capacity of Warmy.io to do extensive email deliverability testing is one of its main advantages. Finding any possible problems that can prevent your email from reaching its recipients is made possible in large part by these checks. Warmy offers you practical information to help you maximise your email campaigns by examining elements including recipient engagement, content quality, and sender reputation.

    Warmy.io also has essential email authentication features. Free record generators are offered for SPF (Sender Policy Framework) and DMARC (Domain-based Message Authentication, Reporting & Conformance). The primary cause of emails being rejected or classified as spam by recipient servers is faked emails, which these tools help to confirm are actually coming from your domain.

    Warmy.io also provides the chance to speak with an email deliverability professional if you run into recurring problems or require specialized guidance. With the support of these professionals, you can overcome difficult problems and improve your email plan to guarantee maximum deliverability.

    You may improve and control your email deliverability proactively by using the features of an email warm-up service such as Warmy.io. This guarantees that your communication stays effective and efficient, reaching your audience uninterrupted, and also helps to avoid SMTP email issues.


    Any organization cannot function well without flawless and efficient email communications, which are maintained by resolving SMTP Email Errors 513, 515, and 517. Unresolved, these mistakes can seriously impede your communication flow, affecting anything from internal operations to customer interactions. Through knowledge of the precise reasons and application of the thorough fixes offered for every problem, you can quickly restore functionality and guarantee the dependability of your email system.

    Further improving your overall email deliverability is taking a proactive approach to email management, such using an email warm-up service like Warmy.io. Warmy.io facilitates the important email deliverability testing, the slow development of a good sending reputation, and the optimization of your email settings for best performance. This fortifies your email communications against possible future interruptions in addition to helping to avoid typical SMTP mistakes.

    Using Warmy.io’s specialised services and the detailed solutions provided for Gmail, Outlook, Yahoo, and other email services, you may build a strong email infrastructure. This proactive approach guarantees that your company communications stay effective and uninterrupted by addressing SMTP failures right away and strengthening your communications infrastructure against future problems.

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