Help: The number you dialed cannot be connected

[cnjowang]

Hi All,
I have a strange issue while using my voxalot (Basic).
Here is detail:
1) I use freedigits and voipdiscount as outbound provider.
2) If I logged in my voxalot account using Zoiper (Which is a softphone), I can dial any outbound number. Everything is ok.
3) If I logged in my voxalot account using Linksys PAP2-NA, same as Zoiper, everything is ok.
4) If I logged in my voxalot account using Linksys WRT54GP2A-AT, when I dial any outbound number, I got "Sorry, the number you dialed cannot be connected", but I can dial other voxalot user and *500, *600.

It's really strange why I have this issue. Anybody can help me?
My voxalot account is 665215

Thanks