CertKitYour cert renewed. The old one is still serving.
LinkedIn renewed 10 days before expiry. It never deployed.
Most automation catches "forgot to renew." Nobody verifies the new cert is what the server is actually sending.
https://www.certkit.io/blog/how-to-verify-certificate-renewal #PKI #TLS
How to verify certificate renewal actually worked
Certbot ran. The logs show success. Exit code 0. LinkedIn found out the hard way that renewed and deployed are not the same thing. The verify step is the part of certificate automation nobody builds until after the outage.