[sr-dev] Need to use kamailio as rtp proxy with sip proxy.

I am totally tired of searching through all your documents for enabling rtp proxy. My use case is, i want to use kamailio as a rtp proxy also with sip proxy. The sip proxy is working good. But for enabling rtp proxy it is returning -3 on rtpproxy_offer and -1 on rtpengine_offer. I have tried both rtp_engine and rtp_proxy. Only thing i need to do is audio between asterisk and twilio trunk should also go through kamailio server. For sip proxy, it is working as expected. Can you just guide me to set up the rtp proxy and complete my project. I will provide my kamailio.cfg file for rtp_proxy(not for rtp_engine). i did not install rtp proxy manually. Should i? i have run this command in terminal. service kamailio restart kamcmd rtpproxy.enable udp:localhost:12221 1 kamcmd rtpproxy.list