GOautodial Open Source Omni-channel Contact Center Suite

Hi,
I am getting the following Warning and I am not able to grab the incoming call

handle_response_invite: Received response: "Forbidden" from '"M3281726180000000008" <sip:CID@server-ip>;tag=as7b21976b'

Any one got this previously please help me to solve this .

Thanks & Regards!