Cant seem to make a call using e164 lookup..

[BlueDream]

I've got family that live a fair distance apart whom are hooked up with VoIP as well as I.

We've both got Voxalot accounts and have registered the appropriate numbers with e164.org and put the appropriate call plan into Voxalot so that it does an ENUM lookup.

When I use the 'dial plan test' function in the voxalot smart call (dial plan) with the number of my family member, voxalot correctly recognises that the number is registered with e164 and forwards it directly to the voxalot account of my family member.

But when I actually dial the number from my phone I get a busy signal.

I've checked to see that the phones are both working normally, by calling them from my mobile and using them to call my mobile - which works fine. It's just when they try to call each other that I'm getting the busy signal.

What could be the cause of this?