Configuring net2phone sip trunk with 3cx

[spartan]

I am having an issue setting up a sip trunk from net2phone on the 3cx. Currently in the port status window on the 3cx it indicates that the trunk is registered and I am also able to make outgoing calls on the trunk however I am unable to receive any calls. N2p tech support says that the trunk is not registered on their network.
Has any one got sip trunking from n2p to work with 3cx if so can you post config details?

Thanks in advance.
A

 

[leejor]

What does the initial registration log look like? It may be a problem related to STUN settings, and registration with an incorrect IP.