I have had several users bring this to my attention wherein their connections timeout. It's an anomaly within X2GO and not anything within the install of QuickBox itself. Sometimes it connects and sometimes it does not. Also, it does not require that users login as root as myself and others have logged in using sudoer accounts. However, I am going to spend some time with this today in an attempt to find why it works for some and doesn't work for others.
If you could provide more info on your settings, OS and Distro then this will provide greater clarity and support to the issue at hand. Also, please provide which session type you are attempting to use on connection... recommended is XFCE.
In regards to root login via ssh, this is not a security issue. The only security issue that will come of root is in regards to weak passwords (which QuickBox is not responsible for managing your level of management on your own system - nor do attempt to tweak the integrity of your server... this is to be solely left to you). At any time you may modify your sshd_config file to say
PermitRootLogin without-password if you have an ssh key (recommended) or
PermitRootLogin no to disable it all together.
Again, thank you for your report and I'll look into this soon.