This is yet another Betamax service. My guess is that for some strange reason their server is only accessible from Portugal on that particular IP address.
Are you using the web application? Or have you set up the parameters on an ATA or a soft phone like X-Lite?
My suggestion would be to try X-lite as a potential solution
You may find some further answers on the Voipbuster forum ...
https://forum.voipbuster.com
Same animal - different name