fix for MODENDP-19

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@5567 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_sofia/sofia.c

@@ -1771,7 +1771,7 @@ void sofia_handle_sip_i_invite(nua_t *nua, sofia_profile_t *profile, nua_handle_
 		is_auth++;
 	}
 	
-	if (!(session = switch_core_session_request(sofia_endpoint_interface, NULL))) {
+	if (!sofia_endpoint_interface || !(session = switch_core_session_request(sofia_endpoint_interface, NULL))) {
 		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Session Alloc Failed!\n");
 		nua_respond(nh, SIP_503_SERVICE_UNAVAILABLE, TAG_END());
 		return;