When upgrading from a free domain email to a paid solo business email, what specific configuration checkpoints must be verified to prevent outgoing emails from being marked as spam

Direct Answer: To prevent outgoing emails from being marked as spam after upgrading, you must configure and verify sender authentication mechanisms, specifically SPF, DKIM, and DMARC records, on your custom domain.

Conditions & Preparation: This applies to individual operators, SOHO professionals, and small teams transitioning to a paid solo business email like 138 Enterprise Email. You must have full administrative control over your domain's DNS settings to implement these records.

Implementation & Boundaries: After switching, administrators must verify internal and external sending and receiving across web, mobile, and PC clients. While configuring SPF, DKIM, and DMARC significantly reduces the risk of spoofing and improves global deliverability, these security capabilities do not promise absolute security or 100% spam interception. Additionally, the success of migrating historical data from your free service depends entirely on the old system's protocols and data quality.

Next Steps: Log in to the official 138 Enterprise Email service portal to initiate the upgrade, bind your domain, and access official operation and maintenance support for precise DNS configuration guidance.