Every bounce message has a reason behind its failure. One sample has been given as follow:
Below there are some common bounce messages have been given with explanation for your assistance.
01. 550 No Such User Here
Explanation: There are no MX records for the recipient’s domain. This message will not deliver. The recipient must create MX records at their DNS host so that they can receive email.
02. Mailbox is full: retry timeout exceeded
Explanation: Sometimes, your mailboxes do not receive new emails and senders receive an error message stating “mailbox is full: retry timeout exceeded”. Usually, this error takes place when you reach to mailbox quota limit.
03. Your domain has exceeded the max defers and failures per hour (5/5 (100%)) allowed. Message discarded.
Explanation: There are generally three circumstances under which this will occur:
- You are sending out mass emails and some of the addresses in your mailing list are inactive and we recommend you to use separate SMTP service.
- Your account has been hacked and is being used to send out spam for a malicious use and you need to change the passwords and to scan your computer through Malware Byte.
- Your website forms (contact/inquiry) are being filled by the spammers for malicious use and Google captcha is required to stop these bounces.
04. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.
Explanation: The recipient cannot verify the existence of your domain. Verify that your domain’s DNS is properly configured or remove the sender from the blacklist.
05. Domain mydomain.com has exceeded the max emails per hour (100/100) allowed.
Explanation:Our datacenter allows to send 100 emails in an hour. If you send more than 100 emails in an hour then you will receive following type of error.
“ Domain my-domain.com has exceeded the max emails per hour (100/100) allowed. ”
This error or bounced generally indicates that our datacenter have a limit defined that allows you to send a limited amount (100) of emails per hour within your domain. That message is an error message from data center. It states that you’ve sent more emails than your allotted per hour limit.
06. Error 503 Valid RCPT command must precede DATA
Explanation: There may be three possible reasons for this bounce message.
- If you do not properly authenticate your SMTP (outgoing mail) connection then this error can occur while sending emails. In order to resolve this issue you would need to enable SMTP authentication. You can consider above screenshot that how can you enable SMTP authentication in Outlook.
- Turn off Antivirus/Windows Firewall temporarily and also Switch off your VPN
- Mailbox is full / Blocks limit exceeded / disk usage limit exceeded
07. The mail server detected your message as spam and has prevented delivery
This error message “The mail server detected your message as spam and has prevented delivery” occurs when the message in the email is marked as spam in recipient end. You need to contact the recipient to request them to add your domain to whitelist or safe sender’s list. After that, the emails will get delivered without any issues. There are also few other reasons why your emails may be detected as spam, especially when sending emails in bulk. Possible reasons include
- The people you are sending the email to have strong spam filter settings on their email account or marked a previous email from you as spam.
- Emails were flagged as suspicious due to the title of the email, for example, they contain obscure characters or titles, or the emails contain too many links.
- Emails sent through Sell have embedded a small tracking pixel, which allows you to see who has opened them. Though very rare, this could cause an email to be flagged as spam by some providers.
- A number of spam filters, such as Gmail and Yahoo, use content filtering to identify potential spam messages. Google’s Bulk Email Guide offers some help on how to structure your emails to minimize the chance of them being flagged.
08. Gmail detected message as unsolicited mail and blocked
Explanation: Need to create/repair DKIM and SPF record in Cpanel > Email Deliverability and the problem will be resolved.
09. Email rejected due to Potentially executable attachment “ForwardedMessage.eml”
Explanation: This issue arises when an email client try sending an email with the attachment of .eml file or try forwarding an email that creates .eml as attachment. This type of file is expressly forbidden from most of the servers due to security risks. We recommend you to zip the .eml files or copy/paste the text of .eml file and remove .eml attachment while sending.
10. Email bounced due to “recipient address rejected”
Explanation: This error normally comes up when the recipient’s email address is not valid or there is some spell mistake while typing the email address. It has also been noticed that in the past an email address does exist but later it was discarded. You would need to contact with the recipient with other mode of the communication to confirm the correct email address.
11. Email bounced due to “the receiving server rejecting your email”
Explanation: Typically, “451 Temporary local problem” error comes due to the email receiving server is rejecting your email. This can happen for a number of reasons but most likely is due to the sending mail server IP is blocked in the email receiving server and you can request them to whitelist your mail server IP address. Another reason could be the receiving mail server being overloaded with messages. Actually, 451 means “Internal resources are temporarily unavailable” and this requires the server to retry the connection later.
12. Email bounced due to “552 5.3.4 Message size exceeds the fixed maximum message size”
Explanation: This particular error is generated when a recipient mail server has size limits in place and the messages exceeded a limit. In order for the messages to be sent, either the size of the messages needs to be reduced or the limit increased. If your message exceeds the limit, you will need to either resize the attachments, or split the message into multiple emails.
13. Email bounced due to “invalid SPF and DKIM record”
Explanation: This error normally comes up when the SPF or DKIM record of sender domain’s is invalid. You would need to repair the SPF and DKIM record for better email deliverability. You can setup these records from Cpanel > Email Deliverability