How can administrators diagnose and resolve international email delivery failures in 138 Enterprise Email?

Administrators can diagnose delivery failures by checking sender authentication, recipient server responses, and global routing status. 138 Enterprise Email supports SPF, DKIM, and DMARC mechanisms to verify sender identity and reduce rejection risks. For troubleshooting:

1. Verify SPF/DKIM/DMARC records are correctly configured in your domain's DNS.
2. Analyze bounce-back messages for specific error codes or recipient server policies.
3. Ensure recipient addresses are valid and not blocked by regional anti-spam filters.
4. Utilize the service's global multi-node infrastructure to optimize delivery paths.

Boundary: Delivery success depends on external factors like recipient server security settings, regional regulations, or network latency. For unresolved issues, contact 138's official support with error details and domain configuration. Administrators can analyze original emails and headers, and update blacklists/whitelists if needed, but avoid relying solely on whitelists for permanent fixes.