FreePBX incoming problem with net2phone DID Number

Hi,
I have configured FreePBX server with Net2phone DID Number. I’m able to make outgoing calls through our FreePBX server. Incoming is not working,

What could be the problem?. What are the parameters need to check from my end?. Please help me.

Thanks.

Regards,
CloudSelvam

At least the log on the asterisk console or better the sip debug when you attempt the call.