No voice of called during a call from a queue

I have created 2 queues and i have add 3 member (2 for one queue and 1 one for other).
I have created the follow extension:
exten =>106,1,Queue(tecnico)
If an internal sip member call 106 the member of tecnico received the call and is all ok)
The probem is when the call arrive from external.
When a person call my number voip and after press 2 to enter in tecnico queue the telephone ring but the caller can’t hear the voice of called but called can hear the voice of caller.
I can’t understand why with internal call the queue work normally (called hear the called and called hear the caller) but from external not.
Help me please.
Thank you

Is this specific to Queue? It sounds like misconfigured NAT, but this would also affect Dial.


exten =>104,1,Answer()
same =>n,Set(CHANNEL(language)=it)
same =>n(voceregistrata),Background(voceregistrata)

exten =>1,1,Dial(SIP/EMANUELE&SIP/PIETRO,20,tTm)
same =>n,Dial(SIP/MARCO,10,tTm)
same =>n,Playback(nbdy-avail-to-take-call)
in this way work

exten =>1,1,Queue(tecnico)

In this way i can hear the voice of caller but caller can’t hear my voice

exten => 106,1,Queue(tecnico) --> in this way i make an internal call and caller and called can communicate.

I have found the problem; is my sip phone linksys.
Is ip phone spa942.
I have try with a normal phone and it is all ok.
Do you know which setting is need to change on my sip phone?