Isso funciona para mim:
exten => 5006005,1,answer() ;same=>n,Set(CONFBRIDGE(user,music_on_hold_when_empty)=no) same=>n,Set(myconference=4000) same=>n,Set(TMP_CONF_COUNT=${CONFBRIDGE_INFO(parties,myconference)}) same=>n,verbose(3," 4000 has users:${TMP_CONF_COUNT}) same=>n,Set(TMP_CONF_LOCKED=${CONFBRIDGE_INFO(locked,myconference)}) same=>n,verbose(3," 4000 has users:${TMP_CONF_COUNT} and lock or unlock:${TMP_CONF_LOCKED}") ;same=>n,Set(TMP_CONF_COUNT=${CONFBRIDGE_INFO(parties,myconference)}) ;remove , in confbridge same=>n,Set(FRAME_TRACE(white)=DTMF_BEGIN,DTMF_END,NULL,IAX,TEXT) same=>n(Press5MuteAll),ConfBridge(4000,,6016adminuser)
ou uma configuração mais simples com menos possibilidade de falha:
exten => 50060055,1,answer()
same=>n(Press5Mute),ConfBridge(4000,default_bridge,6016adminuser,sabse_admin_menu)