sipphone.com and project gizmo

Hi

I signed up for a Project Gizmo account which also gave me a
sipphone.com SIP account. Now on my work machine the project gizmo
client allows me to make and receive calls, it just works with no
configuration on the PC or firewall. However if I try and setup the
sipphone.com settings in x-lite then the firewall blocks the ports. So
my question is how does project gizmo manage to work and how can I
replicate this in x-lite?

Regards

Jon