我有VPN服务器使用Openswan地址103.19.208.247
然后，我想连接我的笔记本电脑（CENTOS）与IP 103.19.208.243到VPN服务器。 在这里我的configuration：
/etc/ipsec.conf
config setup protostack=netkey dumpdir=/var/run/pluto nat_traversal=yes virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4: 25.0.0.0/8,%v4:100.64.0.0/10,%v6:fd00::/8,%v6:fe80::/10 conn L2TP-PSK authby=secret pfs=no auto=add keyingtries=3 ikelifetime=8h rekey=no type=transport left=103.19.208.243 leftprotoport=17/1701 right=103.19.208.247 rightprotoport=17/1701 dpddelay=10 dpdtimeout=90 dpdaction=clear /etc/ipsec.secrets
103.19.208.243 103.19.208.247: PSK "vpnku"
/etc/xl2tpd/xl2tpd.conf
[lac vpn-connection] lns=103.19.208.247 ppp debug = yes pppoptfile = /etc/ppp/options.xl2tpd length bit = yes
/etc/ppp/options.xl2tpd
ipcp-accept-local ipcp-accept-remote require-mschap-v2 refuse-pap ms-dns 8.8.8.8 noccp auth crtscts idle 1800 mtu 1410 mru 1410 nodefaultroute debug lock proxyarp connect-delay 5000 name lele (myvpn username) password nana1234 (my vpn password)
而当我input：IPSec自动启动L2TP-PSK
002 "L2TP-PSK" #10: initiating Quick Mode PSK+ENCRYPT+DONT_REKEY+UP+IKEV1_ALLOW+IKEV2_ALLOW+SAREF_TRACK+IKE_FRAG_ALLOW {using isakmp#1 msgid:ed53b5a6 proposal=defaults pfsgroup=no-pfs} 117 "L2TP-PSK" #10: STATE_QUICK_I1: initiate 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 500ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 1000ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 2000ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 4000ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 8000ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 16000ms for response 010 "L2TP-PSK" #10: STATE_QUICK_I1: retransmission; will wait 32000ms for response 031 "L2TP-PSK" #10: max number of retransmissions (8) reached STATE_QUICK_I1. No acceptable response to our first Quick Mode message: perhaps peer likes no proposal 000 "L2TP-PSK" #10: starting keying attempt 2 of at most 3, but releasing whack
我应该怎么做才能解决这个问题来连接我的VPNServer？
谢谢