SIP/2.0 603 Declined

This response indicates that the callee was contacted but cannot or does not want to participate in the call.

The SIP IP phone can generate this response if the user is using call screening. Upon receiving this response, the phone notifies the user with fast-busy signal and disconnects the call.

The SIP gateway does not generate this response. Upon receiving this response, the gateway initiates a graceful call disconnect and clears the call.

Solution

In Provider's details enter provider's hostname or ip into field Fromdomain.