An administrator is installing an SSL certificate on a new system. During testing, errors indicate that the certificate is not trusted. The administrator has verified with the issuing CA and has validated the private key. Which of the following should the administrator check for next?

The correct answer is "If the root certificate is installed." When an SSL certificate is not trusted, it often means the system cannot validate the certificate's chain of trust back to a trusted root authority. The root certificate, issued by the Certificate Authority (CA), is the anchor of this trust. If the root certificate (or an intermediate certificate in the chain) is missing or not properly installed on the system, the browser or application will not be able to verify the legitimacy of the server's certificate, leading to "not trusted" errors. "If the wildcard certificate is configured" is incorrect because while a wildcard certificate allows a single certificate to secure multiple subdomains, its configuration doesn't directly cause a "not trusted" error if the certificate itself is valid and the chain of trust is intact. "If the certificate signing request is valid" is incorrect because the CSR is used to request the certificate; once the certificate is issued, the CSR's validity is no longer the primary concern for trust issues. "If the public key is configured" is incorrect because the public key is embedded within the certificate itself; if the certificate is installed, its public key is inherently "configured." The issue is about the trust in that certificate, not the presence of its public key.