The error message I'm getting is:
2016-01-01, 14:01:58 VPN Log [grpips0][7] 0.0.0.0/0=== ...109.33.9.231===192.168.5.170/32 #10: [Tunnel Negotiation Fail] DPD: No response from peer - declaring peer dead
2016-01-01, 14:01:58 VPN Log [grpips0]: cmd=down-client peer=109.33.9.231 peer_client=192.168.5.170/32 peer_client_net=192.168.5.170 peer_client_mask=255.255.255.255
2016-01-01, 14:01:58 VPN Log ip route del 192.168.5.170/32 via 62.45.92.1 dev eth1 metric 35
2016-01-01, 14:01:58 VPN Log iptables -t nat -D vpn -d 192.168.5.170/32 -j ACCEPT
2016-01-01, 14:01:58 VPN Log iptables -t nat -D vpn -s 192.168.5.170/32 -j ACCEPT
2016-01-01, 14:01:58 VPN Log iptables -t nat -D vpn_postrouting -d 192.168.5.170/32 -j ACCEPT
2016-01-01, 14:01:58 VPN Log iptables -t nat -D vpn_postrouting -o eth0 -s 192.168.5.170/32 -j ACCEPT
2016-01-01, 14:01:58 VPN Log [grpips0][7] 0.0.0.0/0=== ...109.33.9.231===192.168.5.170/32: [Tunnel Disconnected] instance with peer 109.33.9.231 {isakmp=#0/ipsec=#0}
hope this helps