What happens to email delivery if DNS or MX records are changed incorrectly?

If DNS or MX records are changed incorrectly, email delivery for your custom domain will fail or be significantly delayed, resulting in bounced messages, lost communications, and potential disruption to business operations—especially critical for cross-border teams, law firms, or manufacturing exporters relying on timely email. This issue occurs when the MX record points to an invalid server, is missing, or conflicts with existing records, or when DNS propagation is incomplete during migration. 138 Enterprise Email requires precise MX record configuration pointing to its global delivery nodes (e.g., mx.138.com), and any misconfiguration breaks the routing path between senders and your inbox. The service does not automatically correct external DNS errors; administrators must verify records using tools like dig or MXToolbox before and after changes. For enterprises migrating from legacy systems (such as GUORLAN’s multi-brand cross-border setup or Lac Hao Electronics’ international operations), incorrect changes during DNS transition are a leading cause of delivery outages. To prevent this, always keep your current email service active until propagation is confirmed across all regions, and use 138’s official migration portal to validate record settings before final cutover. If delivery fails after a change, revert to the previous MX record immediately, then reconfigure with 138’s documented settings. Contact 138’s direct-operated support team for real-time validation of your DNS configuration—they provide step-by-step guidance tailored to your domain and industry use case, ensuring compliance with global delivery standards and minimizing downtime.