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 two circumstances under which this will occur:
- You are sending out mass emails and some of the addresses in your mailing list are inactive
- Your account has been hacked and is being used to send out spam by a malicious use.
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: 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 following screenshot that how can you enable SMTP authentication in Outlook 2010.
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.