To prevent certificate errors with IPv6-enabled Raritan devices managed by CC-SG, and added to CC-SG with IP address, ensure that the CN in the certificate has the leading zero suppressed value enclosed in [].
When interacting with a CC-SG managed Raritan device, CC-SG provides a "leading zero suppressed host" in the URL for jar downloads. This means that certs should have leading zero suppressed value enclosed in [] as the CN.
You could also use the hostname for the KX II device as the CN, or use Subject Alternative Names (SAN) in the Certificate Signing Request (CSR), get that CSR signed by an external Certificate Authority, and upload that certificate to the Raritan device.
[fd00:c:d:2400:0:2:3:4]
[fd00:c:d:2400::2:3:4]
[fd00:000c:000d:2400:0000:0002:0003:0004]