cfg_get.pstn.gw_ip="10.0.x.y

route[PSTN] {
#!ifdef WITH_PSTN
	# check if PSTN GW IP is defined
	if (strempty($sel(cfg_get.pstn.gw_ip))) {
		xlog("SCRIPT: PSTN rotuing enabled but pstn.gw_ip not defined\n");
		return;
	}
	if(!($rU=~"^(\+|00)918884978235"))
		return;
	# only local users allowed to call
	if(from_uri!=myself) {
		sl_send_reply("403", "Not Allowed");
		exit;
	}
	$ru = "sip:" + $rU + "@" + $sel(cfg_get.pstn.gw_ip);

	route(RELAY);
	exit;
#!endif

	return;
}

I am able to see kamailio sending INVITE to SIP Provider but no response back. Any other, configuration is required which I'm missing.

I have attached the tcpdump snapshot of the above scenario.

Thanks,

Arish