I have built a PBX by using the Ozeki SDK and and want to connect it to my existing Cisco Unified Communications Manager PBX by using SIP trunking.
By following the instructions of this Cisco setup guide, I have successfully connect the SDK to CUCM, but SIP trunking does not work, because of authentication issues. It sends a 403 response to the Cisco request.
Can anybody give me a checklist to debug or any tips that help to get ahead?
Thanks a lot, guys!