5.1.0 Address Rejected]

Summary:

You are experiencing an error sending a message from [hyundaicnc.co.kr] to [@], with the subject line "Error sending message [1251866644595.2436.114f.eml] from [hyundaicnc.co.kr]." The error is:

550 #5.1.0 Address rejected @

Analysis:

The error message indicates that the recipient's email address, @, has been rejected by the remote SMTP server. The reason for this rejection is not specified in the error message.

Possible Causes:

1. Recipient's Email Address: Check if the recipient's email address is valid and correctly formatted.
2. SMTP Server Configuration: Verify that the SMTP server configuration is correct on both your server (hyundaicnc.co.kr) and the remote server. Make sure that the sender's IP address is allowed to send emails through the remote server.
3. Firewall or Network Issues: Check if there are any firewall rules or network issues blocking the email transmission.

Solution:

1. Check Recipient's Email Address: Verify the recipient's email address and make sure it is correct and valid.
2. SMTP Server Configuration: Double-check the SMTP server configuration on both your server and the remote server to ensure that the sender's IP address is allowed to send emails through the remote server.
3. Troubleshoot Network Issues: If you suspect network issues or firewall rules blocking the email transmission, troubleshoot these issues to resolve the problem.

:

The error message suggests that the recipient's email address has been rejected by the remote SMTP server. To solve this issue, check the recipient's email address and the SMTP server configuration on both your server and the remote server. Additionally, troubleshoot network issues or firewall rules blocking the email transmission.