This Apache error is the equivalent of a "Modulus Mismatch" .
- The Message: It means the certificate (X509) and the private key file defined in your
SSLCertificateKeyFiledirective do not match. - Fix: Double-check your Apache configuration paths. If you are using Hostaday shared hosting, ensure you have selected the correct certificate and key in the SSL/TLS Manager in cPanel . If they still don't match, you must generate a new key and CSR to Reissue the SSL .