NO ringing or connection to another VOIP phone

[mlangbau]

It seems as if my Magicjack works without problems to any normal domestic phone.

However, when calling an American number (516 area code) which is located overseas (VOIP), I get no ringing after I dial, and most of the time, the other side hears a ring, picks up, and cannot hear me.

any suggestions?

(Using a mac OS 10.5.2 on a macbook pro)

Thanks