[Users] no voice when using nathelper with rtpproxy

Hi all I install rtpproxy in the same host (with the public IP) than openser. the installation of rtpproxy put rtpproxy.sock in /var/run directory.But when i make a call between 2 clients (each client in a different LAN), i have no voice after signalisation. And openser give me these errors: [root@Is-dev01 openser-1.0.0-tls]# /usr/local/sbin/openser Listening on udp: 62.128.173.101 [62.128.173.101]:5060 tcp: 62.128.173.101 [62.128.173.101]:5060 Aliases: tcp: 62-128-173-101.iwayafrica.com:5060 udp: 62-128-173-101.iwayafrica.com:5060 WARNING: no fork mode stateless - initializing 0(0) Maxfwd module- initializing textops - initializing 0(0) INFO: udp_init: SO_RCVBUF is initially 110592 0(0) INFO: udp_init: SO_RCVBUF is finally 221184 2(0) INFO: fifo process starting: 20621 2(0) SER: open_uac_fifo: fifo server up at /tmp/ser_fifo... 2(0) INFO: no fifo_db_url given - fifo DB commands disabled! 0(20619) ERROR: force_rtp_proxy2: no available proxies 0(20619) ERROR: force_rtp_proxy2: no available proxies 0(20619) ERROR: unforce_rtp_proxy: no available proxies What's the matter? Best regards Serge