VoipStunt and Voxalot

[tirannus]

Is possible to call a voipstunt user (that use voipstunt software) with sip voip phone ?

I have set Speed dial with :
Number : 1
Name : test
SIP URI sip:Pippo@voipstunt.com

where pippo is the voipstunt username of my friend.

In Dial Plans I have
Priority 1
Pattern _[X*][X*].
Replacement ${EXTEN}
Provider VoipStunt
ENUM ${EXTEN}
Active Yes


When I dial **1 on my voip phone my friend pippo not receive a call, and after 30 seconds in my voip phone appear not reachable (but my friend is online with voipstunt).

Why not work ?