I'm not using Nokia's SIP stack so don't know how it behaves in this kind of situations, but please look into RFC 3261 (SIP: Session Initiation Protocol). There is written:
The callee's machine was successfully contacted but the user
explicitly does not wish to or cannot participate. The response MAY
indicate a better time to call in the Retry-After header field. This
status response is returned only if the client knows that no other
end point will answer the request.
so I'd say that the other client sent this response!
I think I already understand decline
Hello! I believe I have already understood why the recipient sends me decline when I invite him.
I´m using the CSIPExample who cames with the "SIP programmer´s guide". This example makes an invitation without content, i.e., Content-lenght = 0. If I have no more sip applications in my emulator, the recipient sens me decline. When I have other sip app"X" separately, in the recipient appears: "Accept invitation to X from...?", and if the recipient accepts the X app starts.
If somebody doesn´t think this, please, let me know.
What application are you prooving? The chipflip?? If you are using chipflip, you don´t have to change the sipappcapabilities.xml, because it uses sdp lines. If you say in the sipappcapabilities.xml that the sdp is not used, the content-length will be 0, and the recipient will decline, because it doesn´t know what to accept or reject.