Email is still a crucial tool in our digital age. It continues to power communication for businesses and individuals alike. It fuels connections, nurtures leads, and drives sales. But every once in a while, a nightmare can strike. Your beautifully crafted emails that you spent hours working on never reached their intended recipient—the horror! One frequent culprit behind failed deliveries is SMTP Email Error 553 5.1.3.
While frustrating indeed, this error has a fix. So don’t fret. Like the other errors under the Simple Mail Transfer Protocol (SMTP) family, SMTP Email Error 553 5.1.3 can also be conquered.
This guide contains the specifics of SMTP Email Error 553 5.1.3. We’ve also compiled solutions to keep your email communication smooth and stress-free, ensuring your emails land in inboxes.
This error means there’s a problem or issue with the format of the recipient’s email address. Maybe there’s a typo. Some special characters are unsupported. Sometimes, the email address format is not recognized as valid by the email server.
Users encountering this issue might see messages such as:
- “553 5.1.3 The recipient address <email_address> is not a valid RFC-5321 address.”
- “Error 553 5.1.3: <email_address>… User address is malformed.”
- “Failed to send; SMTP server error 553 5.1.3 <email_address>… Syntax error in mailbox address.”
SMTP Email Error 553 5.1.3 can arise from several factors, primarily related to issues with the email address format being sent to. Understanding these common causes can help in effectively diagnosing and solving the problem:
The most straightforward reason is simply typing the email address incorrectly. This could mean misspelling the address, omitting characters, or including spaces and special characters that aren’t typically part of email formats.
Some email servers have strict rules about which characters can appear in an email address. Using unsupported characters (even if they’re technically valid in other contexts) can trigger SMTP Email Error 553 5.1.3.
Email addresses should always follow a specific format, which is name@domain.com. So if an email address doesn’t follow this, or misses the “@” symbol or the domain part, this will lead to an error.
Sometimes, the way an email client (like Outlook or Gmail) is configured can cause it to incorrectly format outgoing email addresses. Yes, even if you’ve entered them correctly.
Misconfigured MX records on the receiver’s end can lead to undelivered emails. Though this can also generate different error codes, it’s still worth reviewing if the format is correct.
There’s no need to worry when you see this error. However, knowing how to resolve this will help you determine your next steps.
- Verify email address format. Review the recipient’s email address for any typos or formatting errors. Make sure it follows the required format.
- Check account settings. Go to Settings > See all settings > Accounts and Import. Under “Send mail as,” ensure the email address is correctly formatted and verified.
- Review SMTP settings. Ensure that the SMTP server is set to smtp.gmail.com, the port is set to 587 (for TLS) or 465 (for SSL), and that “Use Authentication” is enabled with your correct Gmail address and password
- Verify your email address. Similar to Gmail, start by reviewing and verifying the format of the recipient’s email address.
- Adjust email account settings. Head over to File > Account Settings > Server Settings. Click on Outgoing Mail and confirm the SMTP settings are correct: server smtp-mail.outlook.com, port 587, and encryption method TLS.
- Ensure correct authentication. Look for “My outgoing (SMTP) server requires authentication” and “Use the same settings as my incoming mail server” and ensure they are checked or selected.
- Check the recipient’s email address. Make sure it is free of errors and formatted correctly.
- Review your SMTP configuration settings. Go to Account Info > Account Security > Manage App Passwords. Select your email app and generate a unique app password. Use this app password with your email address to authenticate your SMTP server.
- Check your SMTP server details. Set to smtp.mail.yahoo.com, with port 465 (SSL required) or 587 (TLS required).
Email warmup tools don’t just help prevent SMTP errors. It’s more for the long run. Warmy.io, for example, not only reduces the chances of encountering errors like SMTP Email Error 553 5.1.3, it also gradually builds your sender reputation. Warmy.io does this by gradually increasing the volume of emails sent from your email, mimicking human-like activity to establish your reputation with email service providers and ISPs.
Benefits of using email warmup services:
- Builds sender reputation. Sending more emails gradually over time helps in building a positive sender reputation.
- Reduces email bounces. When you have a better sender reputation, this reduces the likelihood of your emails bouncing or being marked as spam.
- Prevents blacklisting. A good sender reputation also helps in preventing your email domain from being blacklisted by major email service providers. It sends a message that you are safe and you are reliable.
- Improves email engagement rates. Emails that land in inboxes have bigger chances to be opened, read, and clicked on. So this essentially improves overall engagement rates.
Warmy.io also offers additional tools that complement its warmup service, further ensuring your emails are delivered successfully:
- Free Email Deliverability Test. Get the real deal and valuable insights on how likely your emails are to be delivered to your recipient’s inbox, providing insights on areas for improvement.
- Blacklist Checks. Warmy.io can check if your email domain has been blacklisted, which is a common cause of email delivery issues.
- SPF and DMARC Record Generators. Warmy.io provides tools to generate these records for free, helping you comply with email security standards and improve deliverability.
Addressing SMTP Email Error 553 5.1.3 quickly is crucial for maintaining uninterrupted email communication, crucial for today’s digital interactions. This guide has provided practical solutions for popular email platforms and highlighted the preventive benefits of email warmup services like Warmy.io.
These strategies can ensure your emails consistently reach their intended recipients. So take action now to safeguard your email delivery and keep your professional connections strong.
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