What is Blacklisted Certificates check in SSL/TLS Certificate monitoring ?

What is Blacklisted Certificates check in SSL/TLS Certificate monitoring ?

      
       The blacklist check ensures that the server’s SSL/TLS certificate is not blacklisted by comparing its SHA-256 fingerprint with a list of known blacklisted certificates. This process helps identify certificates that are associated with cyberthreats or compromised entities. The SSL Blacklist (SSLBL) uses SHA-256 fingerprints to track blacklisted certificates, preventing the use of untrusted certificates in secure communications.