Below are the examples of bounced messages received through different email systems:
Custom DNS:
If you use Kolleno Custom DNS feature to deliver emails, it can come back with an error message such as:
An error occurred while trying to deliver the mail to the following recipients: client@example.com
Other email connections:
In many cases, it will be something that is called a “550 permanent failure for one or more recipients.”
There are several possible causes for an email not getting delivered:
Invalid email address: One or more of the recipients’ email addresses may be invalid or mistyped, causing the email server to fail in delivering the message. Double-check the recipient email addresses for any typos or mistakes, and also visit the domain name of the email address to check if it is valid.
Recipient’s mailbox is full: If the recipient’s mailbox is full and cannot accept any more messages, the server will return a “550 permanent failure” error. In this case, the recipient needs to clear some space in their mailbox to receive new emails.
Recipient’s email server is down: If the recipient’s email server is experiencing technical issues or is temporarily down, the email cannot be delivered, and the server will return a 550 error.
Domain or email server configuration issues: Sometimes, issues with the configuration of the recipient’s email server or domain settings can result in failed deliveries.
Email filtering or blocking: The recipient’s email server may have strict filtering rules or could have blocked the sender’s email address or domain, causing the delivery failure.
Sender’s email server reputation: If the sender’s email server has a poor reputation, it may get blocked or rejected by the recipient’s email server.
IP blacklisting: The sender’s IP address might be blacklisted by the recipient’s email server or spam filters due to suspicious activity or a history of sending spam.
PLEASE NOTE:
Kolleno has seen that happened in the past when users try to email clients that have their email servers protected by Barracuda Networks.
The email that caused the error may show as “Read & Clicked” because the firewall at the client would have a bot that clicks on the links to check them.