The GMO Cloud Hosting Console is pre run by java. Make sure that there is a java application installed and updated.
Also it has been known that the browser of IE (Internet Explore) may not work in opening Cloud Console tab through your Portal.
If you are not able to log in your Portal but Console tab is not working, please try to use the other browser such as Firefox or Google Chrome.
If that does not work, please contact support at firstname.lastname@example.org