550 #5.7.1 spf unauthorized mail is prohibited

A DNS-related issue!

The error message "550 #5.7.1 SPF unauthorized mail is prohibited" is a response from a mail server indicating that the email you're trying to send is being blocked due to a Sender Policy Framework (SPF) issue.

Here's a breakdown of the error message:

• 550: This is the SMTP response code indicating that the email was rejected.
• #5.7.1: This is the specific error code, which is a sub-code of the 550 response code. In this case, 5.7.1 is a generic error code indicating that the email was rejected due to a policy violation.
• SPF unauthorized mail is prohibited: This is the human-readable error message, which explains that the email was blocked because it appears to be sent from an unauthorized IP address or domain.

SPF is a security protocol designed to prevent email spoofing by verifying that emails are sent from authorized IP addresses or domains. When a mail server receives an email, it checks the sender's IP address or domain against a list of authorized senders specified in the sender's DNS records. If the sender's IP address or domain is not authorized, the email is blocked.

To resolve this issue, you'll need to ensure that your email server's DNS records are properly configured to include the authorized IP addresses or domains. Here are some steps to help you troubleshoot the issue:

1. Check your DNS records: Verify that your DNS records include the correct IP addresses or domains authorized to send emails on behalf of your domain.
2. Check your SPF record: Ensure that your SPF record is correctly configured and includes the authorized IP addresses or domains.
3. Check your DKIM record: If you're using DKIM (DomainKeys Identified Mail) to sign your emails, ensure that your DKIM record is correctly configured and includes the authorized IP addresses or domains.
4. Check your email server configuration: Verify that your email server is configured to use the correct DNS records and that the email server is not blocking the email due to a misconfigured setting.

If you're still having trouble resolving the issue, you may want to consult with your email provider or a DNS expert to help you troubleshoot the problem.