Why are Gmail accounts bouncing and showing 'No Such User' errors?

Summary

Gmail accounts bounce with 'No Such User' errors due to a combination of factors. These include temporary Gmail-specific issues, mistyped or non-existent email addresses, suspended or deleted accounts (including aliases), incorrect domain MX records, temporary server issues, inaccurate email verification services, and poor email list hygiene. A surge in these bounces was noted around December 2020. Proper list hygiene, MX record configuration, and validating email addresses are essential to mitigate these issues.

Key findings

  • Address Validity: The primary reason for 'No Such User' errors is that the email address is invalid or doesn't exist on the mail server.
  • Typographical Errors: Simple typos in the email address are a significant cause, often missed even by validation services.
  • Account Status: The recipient's account might be suspended, deleted, or inactive.
  • MX Record Configuration: Incorrectly set up MX records prevent proper email delivery to the domain.
  • Gmail Issues: Temporary server issues or broader Gmail outages can cause valid addresses to bounce.
  • List Hygiene: Outdated and poorly maintained email lists contribute significantly to bounce rates.
  • Verification Inaccuracies: Email verification services can sometimes incorrectly flag valid addresses as invalid.

Key considerations

  • Validate Addresses: Always double-check email addresses for typos or inaccuracies.
  • Monitor Gmail Status: Stay informed about potential Gmail outages or server issues.
  • Check Account Status: If possible, confirm the recipient's account is active and valid.
  • Verify MX Records: Ensure MX records for your domain are correctly configured.
  • Clean Email Lists: Regularly remove inactive or invalid addresses from your email lists.
  • Evaluate Verification Services: Assess the accuracy of your email verification service and consider alternatives if necessary.
  • Resend After Delay: If a temporary server issue is suspected, try resending the email later.

What email marketers say
21Marketer opinions

Gmail accounts bounce with 'No Such User' errors due to various reasons including: temporary Gmail issues, mistyped or non-existent email addresses, suspended accounts, incorrect domain MX records, deleted accounts (including aliases), temporary server issues, email verification services incorrectly marking addresses as invalid, or poor email list hygiene. Early December 2020 saw a spike in these issues. Checking for typos, verifying MX records, and maintaining clean email lists are recommended.

Key opinions

  • Gmail Issues: Temporary issues on Gmail's end can trigger 'No Such User' errors, particularly noted in early December 2020.
  • Typographical Errors: Mistyped email addresses are a common cause.
  • Account Status: The recipient's account may be deleted, suspended, or simply not exist.
  • MX Record Configuration: Incorrectly configured MX records for the domain can lead to delivery failures.
  • List Hygiene: Poor email list hygiene, including outdated or inactive addresses, contributes to bounces.
  • Verification Service Errors: Third-party email verification services might incorrectly mark valid addresses as invalid.

Key considerations

  • Double-Check Addresses: Always verify the recipient's email address for typos or errors.
  • Monitor Gmail Status: Be aware of potential widespread Gmail issues that may cause temporary bounces.
  • Review Account Status: If possible, confirm with the recipient that their account is active and valid.
  • Verify MX Records: Ensure the domain's MX records are correctly configured to point to Gmail.
  • Maintain List Hygiene: Regularly clean your email lists to remove inactive and invalid addresses.
  • Review Verification Practices: Evaluate the accuracy and reliability of any email verification services used.
  • Resend After Delay: If a temporary server issue is suspected, try resending the email after a short delay.
Marketer view

Email marketer from Email Geeks shares experiencing a sudden deliverability hit.

June 2023 - Email Geeks
Marketer view

Email marketer from Email Geeks shares an email sent from personal Gmail account to another Gmail account bounced with "550 5.1.1 The email account that you tried to reach does not exist."

July 2024 - Email Geeks
Marketer view

Email marketer from Email on Acid explains that sometimes, temporary server issues at Gmail's end can cause 'No Such User' errors even when the email address is valid. They recommend retrying sending the email after some time to see if the issue resolves itself.

October 2023 - Email on Acid
Marketer view

Email marketer from Stack Overflow explains that 'No Such User' errors can happen because the account genuinely doesn't exist, there was a typo in the email address, the domain part of the address is incorrect, or there are temporary issues at the recipient's mail server.

April 2022 - Stack Overflow
Marketer view

Email marketer from Litmus shares that basic email address typos and errors are a main cause for no such email errors - even with validation services active, it may not catch a simple typo.

August 2022 - Litmus
Marketer view

Email marketer from Email Geeks shares having 26,279 "The email account that you tried to reach does not exist" responses from Gmail.

September 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks confirms getting the same bounce issues from Gmail.

September 2024 - Email Geeks
Marketer view

Email marketer from Reddit answers that a 'No Such User' error can occur if the Gmail account has been suspended by Google due to policy violations or other reasons. The user recommends contacting Google Support if the account suspension is believed to be in error.

November 2024 - Reddit
Marketer view

Email marketer from Email Geeks confirms getting the same bounce issues from Gmail.

September 2024 - Email Geeks
Marketer view

Email marketer from Email Geeks shares that the problem still seems to persist with higher than usual bounces.

December 2023 - Email Geeks
Marketer view

Email marketer from ActiveCampaign explains that regularly cleaning your email lists and removing inactive subscribers can help prevent 'No Such User' errors. Over time, email addresses can become invalid, and keeping lists up to date improves deliverability.

August 2021 - ActiveCampaign
Marketer view

Email marketer from MXToolbox explains that 'No Such User' errors occur when an email is sent to an address that is syntactically incorrect (e.g., missing '@' symbol, invalid characters) or the recipient's domain does not exist. They suggest using their email validation tools to check the validity of email addresses.

October 2022 - MXToolbox
Marketer view

Email marketer from Quora explains that if the domain's MX records are not correctly set up to point to Gmail, emails sent to addresses at that domain may result in 'No Such User' errors, even if the user exists. Proper MX record configuration is essential for email delivery.

March 2024 - Quora
Marketer view

Email marketer from Email Geeks shares tested with his personal gmail account and got the same bounce message.

April 2024 - Email Geeks
Marketer view

Email marketer from Email Geeks shares that the timeframe impacted was roughly from 4pm to 7pm ET based on his mailer stats.

April 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks shares that some people and ESPs are reporting Gmail might be having issues, seeing more emails bounce as “NoSuchUser” and refers to a downdetector link.

February 2023 - Email Geeks
Marketer view

Email marketer from Super User suggests that if a user has deleted their Gmail account or an alias associated with that account, sending an email to that address will result in a 'No Such User' error. The user notes that it is important to check for aliases when troubleshooting bounce messages.

June 2021 - Super User
Marketer view

Email marketer from Google Support explains that a 'No Such User' error can occur if the recipient's email address is mistyped or no longer exists. They recommend double-checking the address for typos and unnecessary spaces. The account may have also been deleted by the user.

June 2021 - Google Support
Marketer view

Email marketer from Email Geeks shares seeing these bounces starting up again in bulk at 2020-12-15 19:55:00UTC.

May 2022 - Email Geeks
Marketer view

Email marketer from Email Geeks notes seeing bounce issues between 2:30pm - 5pm PT based on a small sample size of clients.

September 2021 - Email Geeks
Marketer view

Email marketer from Reddit user explains that often businesses use third party email verification services that can sometimes mark an address as invalid. They suggest that the recipient could have accidentally unsubscribed and it's been incorrectly marked as a 'No Such User'.

October 2024 - Reddit

What the experts say
2Expert opinions

Gmail accounts bounce with 'No Such User' errors primarily because the email address doesn't exist on the mail server. This can result from typos, closed accounts, or misconfigured domain settings. Maintaining good list hygiene, which includes regularly cleaning email lists and verifying domain records, is crucial to prevent these bounces.

Key opinions

  • Non-Existent User: 'No Such User' errors indicate the email address is not valid on the receiving mail server.
  • Possible Causes: Typographical errors, closed accounts, and improper domain configuration are common reasons.
  • List Hygiene Importance: Maintaining a clean and up-to-date email list significantly reduces 'No Such User' bounces.

Key considerations

  • Address Verification: Double-check email addresses for any typos before sending.
  • List Maintenance: Regularly remove inactive or invalid email addresses from your mailing lists.
  • Domain Configuration: Ensure the email domain is correctly configured to receive email.
  • Server Blocks: Check if the sending server is blocked by the receiving mail server.
Expert view

Expert from Spamresource.com explains that a "No Such User" error (or similar variations like "User unknown", "Invalid recipient", "Recipient address rejected") usually signifies that the email address you're trying to reach doesn't exist on the mail server. This can be due to typos in the email address, the account being closed, or the domain itself not being properly configured to receive email. It can also happen if the sending server is blocked.

February 2023 - Spamresource.com
Expert view

Expert from Word to the Wise shares that list hygiene is a huge part of avoiding bounces including 'No Such User' bounces. Regularly cleaning your email list and removing inactive or invalid addresses is crucial. Also checking for updated domain records will help.

June 2023 - Word to the Wise

What the documentation says
3Technical articles

Gmail 'No Such User' errors, indicated by SMTP error codes 550 and 5.1.1, signal that the recipient's mailbox is unavailable due to the user not existing, the address being incorrect, account suspension/deletion, or routing problems. Proper domain configuration and checking for address accuracy are critical.

Key findings

  • SMTP Error Codes: 550 and 5.1.1 error codes indicate 'No Such User' conditions.
  • Unavailable Mailbox: The mailbox is inaccessible due to the user not existing or other issues.
  • Possible Causes: Incorrect address, account suspension/deletion, and routing problems are possible reasons.

Key considerations

  • Address Accuracy: Verify the recipient's email address is correct.
  • Account Status: Consider the possibility of the account being suspended or deleted.
  • Domain Configuration: Ensure the domain is properly configured for email delivery.
  • Routing Issues: Investigate potential routing problems within Google's infrastructure.
Technical article

Documentation from IETF specifies that a 5.1.1 enhanced status code in SMTP responses indicates that the recipient address does not exist. This code is specifically used for 'bad destination mailbox address' scenarios.

June 2021 - IETF
Technical article

Documentation from Google Workspace Admin Help explains that 'No Such User' bounce messages can indicate that the recipient’s email address is incorrect, the user's account has been deleted or suspended, or there are routing problems within Google's infrastructure. It also suggests checking if the domain exists and is configured correctly.

October 2021 - Google Workspace Admin Help
Technical article

Documentation from RFC Editor explains that a 550 SMTP error code, often associated with 'No Such User' errors, indicates that the mailbox is unavailable because the user does not exist on the receiving system or the mailbox is inaccessible.

August 2021 - RFC Editor