When you land on a site like opencdnbdfctn.jomodns.com and can't even reach it because of a certificate mismatch, that's a serious warning sign. Legitimate CDN endpoints or content delivery services always have valid SSL certificates that match the domain. Here, the certificate belongs to entirely different businesses like Dianping and Meituan, not this domain — that's a configuration error at best, and a phishing attempt at worst.
There is no ownership information, no about page, and no contact details anywhere. The domain itself isn't even registered in public WHOIS records, which is highly unusual for any operational service. While the site isn't on any blacklists yet, that doesn't make up for the fact that its operator chose to remain anonymous and let security lapse.
For anyone wondering 'is opencdnbdfctn.jomodns.com fake?' — the evidence points to a site that cannot be trusted. There is no way to verify its purpose, and the technical failures suggest it isn't maintained properly. Avoid entering any data or even visiting it until the certificate and ownership issues are resolved.