Works for me, on iPhone, but I'm not using an access key, I'm using the server IP address + port number.
Couple of things you could try at home...
Turn off WiFi on your phone and switch to your carrier's data connection.
Try connecting by setting the external IP and port number in the JRemote settings... does that work?
If it does, it suggests that there's either something out of date with your access key or something is wrong with access key connection in JRemote.
You could try generating a new access key, which should start off with all your current connection options, and see if that works?
Although, having said that, if Gizmo connects externally using your current access key, it kind of suggests that something might be up with JRemote?
I'll test with access key when I get home and let you know what happens...