If you try to connect to your server via Supermicro IPMIView and launch a Java KVM session, you may receive "Connection refused" error message.

Supermicro switched to using stunnel to securely tunnel KVM traffic and this error is generally related to a time error with the certificate. The fix requires ensuring the BMC time is set correctly. This can be done either through ipmitools via the CLI on your server or contact tech support and request it to be checked.