event ID warning/error while try to request a certificate

hey everone

yesterday i handle with my ca server event ID warning/error while try to request a certificate:


Active Directory Certificate Services %1 will reduce the maximum lifetime of the issued certificate for request %2 because the lifetime of the CA certificate is shorter than the validity period set in the registry. Consider renewing the CA certificate or reducing the validity period in the registry.

i count on anyone here that bring me a little piece of information

thanks

vadim