run the below from command prompt
javaws -verbose siperian-console.jnlp
See what exact error it is throwing.
If the JNLP is downloadable, then download it into a local directory. Open it in notepad and see what is the servername, host and port details inside the JNLP. Sometimes, the host might be referred with a host name instead of IP address and you might able to open the hub console because of firewall issues.
If JNLP content has a hostname instead of IP address, change it manually and open this local JNLP through a browser.
If this test works, then you need to update cmxserver.properties with the IP address in the hostname property.
You will get error details in console.log for more details on why error is coming.
If you can paste it here, will narrow it down on cause of this issue.
please clear java cahe