If a certificate has expired or you are unable to resolve an error, you might want to delete a certificate.
IMPORTANT:Use caution when deleting certificates. You should never delete system-generated certificates.
In the browser-based management tool, click Home > Certificate Maintenance > a certificate you have generated that has expired or has an unresolvable error.
Click Delete.
In the Delete Certificate dialog box, click Yes.
The certificate is removed from the certificates list.
If you have deleted the certificate in error, click Cancel.
Click Apply to remove the certificate from the appliance.
After clicking Apply, the certificate cannot be restored unless you have created a backup copy.