What Does My Email Bounce Mean?
Occasionally, we may receive reports from our customers that they've gotten a bounceback when sending an email. An email bounce is generated when there is a problem with the server sending or receiving the mail. The bounceback error typically gives us some information about whatever is causing the problem. Knowing how to decode bounceback messages will be necessary to guide the customer to the correct resolution. You can check bouncebacks received through Splunk.
In this article, we'll discuss:
Email Bounceback
You can check bouncebacks received through Splunk. Below is a list of potential bounceback errors and their meanings.
| Type of Bounceback | Bounceback Message | Reason/Meaning | Resolution |
| Quota/Limit Related Bounceback Message (Incoming) | SMTP 421 (Server Temporarily Not Available) | A temporary fail due to a full mail queue. | Try sending the email later. |
| SMTP 550 ("fromemail" max messages per session) | Several emails were sent simultaneously. Exceeded email limits. | Try sending the email later. | |
| Receiver Account-Related Bounceback Message (Incoming) | SMTP 452 ("toemail" requested action aborted: try again later - GL/GL) | Momentary fail due to the account using greylisting. It will be accepted when the delivery is retried. | The account is using greylisting, so try sending the email later. |
| SMTP 550 ("fromemail" sender rejected) | Email address is not formatted correctly(no @domain). | Make sure to put in the correct email address. It should be properly formatted. | |
| SMTP 550 ("toemail" recipient rejected GL/BL) | This is a permanent failure: The sender has been blacklisted by the recipient (the customer has blacklisted them). | Reach out to the recipient through alternative methods. It’s possible that your email address was accidentally blacklisted. | |
| SMTP 550 ("toemail" recipient rejected) | The recipient’s mailbox does not exist. | Remove the invalid email address. | |
| Content-Related Bounceback Message (Incoming) | SMTP 452 ("toemail" requested action aborted: try again later - GL/GL) | Momentary fail due to the account using greylisting. It will be accepted when the delivery is retried. | The account is using greylisting so try sending the email later. |
| SMTP 421 (Temporary Rejection. Reverse DNS for "IP" failed) | This is an SMTP momentary rejection. Unable to identify the PTR record. | Ensure that the IP address has a reverse DNS setup before attempting to resend the email. | |
| SMTP 552 (Remote MTA $ip: A URL contained in this message is blacklisted by Spamhaus DBL. See http://www.spamhaus.org/dbl) | The URL in the body is blacklisted. | Remove the URL from the email body and resend it. | |
| SMTP 552 (virus-infected message rejected) | Cloudmark identified the message as containing a virus. | Give an option to opt-out in your email messages. Check the sending lists to ensure the recipients are correct. If the message was flagged in error, please save the original email copy and let us know by reporting it. | |
| SMTP 552 (virus-infected message rejected) | The Sender attached something in a file format (.com .bat .btm .cmd .cpl .dll .exe .lnk .msi .pif .prf .reg .scr .vbs) that our server does not allow. | Give an option to opt-out in your email messages. Check the sending lists to ensure the recipients are correct. If the message was flagged in error, please save the original email copy and let us know by reporting it. | |
| SMTP 554 (Connection refused - "IP") | Based on CSI, This is rejected for spam. | Verify the IP address reputation of the sender using Cloudmark Sender Intelligence (CSI). | |
| SMTP 554 (Connection Rejected. Reverse DNS for "IP" does not exist) | This is a permanent rejection. The sender does not have a PTR record. | The incoming server considers your email as spam or has blacklisted your IP address. | |
| Common Outgoing Bounceback Message | Reject connection SMTP 554 (rejected for policy reasons) | It was blacklisted or flagged as likely spam. The recipient server questions the sender’s authenticity or the content of the message. | Check and review if the IP is listed on the Policy Block List of Spamhaus. |
| Reject SMTP 550 ($toemail recipient rejected - ERR016) | The recipient is blocked for blacklisting, spam, or email limit purposes. | Please contact the sender to review their server logs for the exact reason behind the email rejection. Additionally, advise them to whitelist our mail server hostname and your email address in their spam filter. After these steps, resend the email and see if it will be delivered. | |
| SMTP 452 ("fromemail" sender rejected. Too many messages for this connection ERR034) | Several emails were sent simultaneously. Exceeded email limits. | Try sending the email later. | |
| SMTP 550 ("fromemail" sender rejected - ERR082) | The recipient is blocked for blacklisting, spam, or email limit purposes. | Please contact the sender to review their server logs for the exact reason behind the email rejection. Additionally, advise them to whitelist our mail server hostname and your email address in their spam filter. After these steps, resend the email and see if it will be delivered. | |
| SMTP 550 ("fromemail" sender rejected - ERR081) | The domain name is blacklisted. | This is most probably because the receiver blocked your domain, which resulted in the email not going through. We recommend having the domain name whitelisted on the receiver’s server. | |
| SMTP 550 ("fromemail" suspect invalid mailer domain; please check your DNS records - ERR006) | The sender's email is sent as an IP address. | Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| SMTP 550 ("fromemail" Suspect invalid mailer domain; please check your DNS records - ERR007) | A or MX records don't exist. | Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| SMTP 550 ("fromemail" Suspect invalid mailer domain; please check your DNS records - ERR008) | DNS check fails. | Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| SMTP 550 ("fromemail" Suspect invalid mailer domain; please check your DNS records - ERR009) | A or MX record invalid. | Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| SMTP 550 ($toemail recipient is invalid - ERR010) | The recipient's email is an IP. | Confirm the email address with the customer and ask them to verify its spelling. Suggest to him to retry sending. | |
| SMTP 550 ($toemail recipient is invalid - ERR011) | Recipient DNS check fails. | Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| SMTP 550 ($toemail recipient is invalid - ERR013) | The recipient domain is not FQDN. | Confirm the email address with the customer and ask them to verify its spelling. Suggest to him to retry sending. | |
| SMTP 550 ($toemail recipient is invalid - ERR014) | The recipient's email is not a valid email address/domain. | Try sending the email later. | |
| Error 550: You have reached the maximum number of messages per session. | The IP address has reached the maximum number of messages allowed for that particular session. | Try sending the email later. | |
| Reported error: 550 The Domain Name System (DNS) reported that the recipient's domain does not exist. |
|
Validate your existing DNS records. The issue might be due to a misconfiguration of DNS, an SPF or DKIM record preventing email reception, or blacklisting of the email address/domain. Ensure all records are up to date. Additionally, try whitelisting the email and resend it. | |
| UCE ( Unsolicited Commercial Email ) is strictly prohibited. | The recipient is sending unsolicited emails to individuals without prior explicit consent or any prior acquaintance. |
Blacklisted, Blocked, or Rejected Messages
Warning: Issues involving blacklists or blocking by other hosts or email services will require resolution via those 3rd parties.
The unending struggle of mail providers against spam can sometimes catch a mail service in the crossfire. At the worst, an email address or domain may be blacklisted. Blocking or rejecting email messages is also possible and may show specific errors or more generic ones.
Warning: An email blacklist or block may trigger if the email account is forwarding large amounts of mail. Bluehost recommends using a mail fetcher instead of a forwarder as a solution.
550 and 451 errors
550 SMTP Error or 550 Sender Verify Failed
This error indicates the mail server is not configured to handle mail correctly for the domain. This can happen if recent changes to the domain's Mail Exchange (MX) or DNS records or if the mail server is different from the website's server. Please refer to the live article Mail Exchange Record and what to put for your MX Record.
550 Access Denied - Invalid HELO Name
The most common reason for this error message is incomplete or incorrect email client settings. This is the program on the customer's computer that allows them to access the email, such as Outlook or Thunderbird. Please refer the customer to our live article, Email Connection Settings, and ensure the correct server settings are being used within the email client.
550 Dictionary Attack
This error may show in a bounceback due to your mail program sending an incorrect log-in password multiple times and may have been flagged as a dictionary attack. The customer will need to stop sending emails and halt any mailing lists. If a temporary restriction ware placed on the account, the customer would need to wait 1 hour for that restriction to be removed. Assist the customer in ensuring their email client settings use the correct password and server credentials by referring them to the live article Email Connection Settings.
550 Ip.Add.Re.Ss is not Allowed to Send Mail from domain.com
This bounceback error occurs when the server is not authorized to send mail using the domain in question. This is caused when a Server Policy Framework record, also known as an SPF record, is set to either specifically block the server's IP or does not authorize the domain to send mail when it ends with a deny rule. Please refer the customer to the live article SPF Records and assist them in setting the server's default record.
550 Access Denied - Invalid HELO Name
The most common reason for this error message is incomplete or incorrect email client settings. This is the program on the customer's computer that allows them to access the email, such as Outlook or Thunderbird. Please refer the customer to our live article, Email Connection Settings, and ensure the correct server settings are being used within the email client.
451 - Error While Writing Spool File
This error generally indicates a temporary issue that typically resolves itself. However, it could also indicate incorrect email settings within the email client. Please refer the customer to the live article Email Connection Settings and assist the customer in ensuring the correct settings are being used.
Summary
Email bounces are a very common occurrence. Thus, they can easily be solved by understanding error messages and taking the appropriate course of action. Now that you have followed through all the steps outlined here to troubleshoot and fix issues, your emails will start bounces. If it requires further assistance, please note that Bluehost is with you to ensure delivery and success of your email.
If you need further assistance, feel free to contact us via Chat or Phone:
- Chat Support - While on our website, you should see a CHAT bubble in the bottom right-hand corner of the page. Click anywhere on the bubble to begin a chat session.
- Phone Support -
- US: 888-401-4678
- International: +1 801-765-9400
You may also refer to our Knowledge Base articles to help answer common questions and guide you through various setup, configuration, and troubleshooting steps.