If you are receiving a message indicating that your emails are being blocked due to being on a blacklist, you can take the following steps to address the issue:
- Identify the Error Code: The error message you received includes a specific error code (550 5.7.1), which indicates that your sending IP address is blocked. This is a common issue when the IP address has been flagged for sending spam or malicious content.
- Use the Delist Portal: You can request removal from the Microsoft 365 blocked senders list by using the Office 365 Anti-Spam IP Delist Portal. Visit sender.office.com to submit your request.
- Contact Your ISP: The error message suggests contacting your Internet Service Provider (ISP) since part of their network is on the block list. They may need to take action to resolve the issue.
- Follow Best Practices: Ensure that you are following best practices for sending emails to avoid being flagged in the future. This includes proper email authentication and maintaining a good sender reputation.
- Monitor Your Email Sending Practices: Regularly check your email sending practices and ensure that your domain is not compromised or misused for sending spam.
If you continue to experience issues, consider reaching out to Microsoft Support for further assistance.
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