[strongSwan] ignoring request with ID 1,already processing

[ili]

Hi,
   I want to use the external dhcp function of strongswan to allocate IP to the 
client,but there is always existing errors as follows:
...
localhost charon:13[IKE] peer requested virtual IP %any
localhost charon:13[IKE] sending DHCP DISCOVER to 10.10.10.20
localhost last message repeated 2 times
localhost charon:09[MGR] ignoring request with ID 1,already processing
localhost charon:13[CFG] sending DHCP DISCOVER to 10.10.10.20
localhost charon:13[IKE] sending DHCP DISCOVER to 10.10.10.20
localhost charon:05[MGR] ignoring request with ID 1,already processing
localhost charon:13[CFG] DHCP DISCOVER timed out
localhost charon:13[CFG] acquiring address from pool 'dhcp'failed
localhost charon:13[CFG] no virtual IP found,sending INTERNAL_ADDRESS_FAILURE
localhost charon:13[CFG] configuration payload negotiation failed,no CHILD_SA 
built
...

10.10.10.20 is my SecGW's IP.

Is the problem of dhcpd.conf or strongswan.conf ? 


The strongswan.conf :
charon{
         ...
         plugins{
                ...
                dhcp
                {
                   server = 10.10.10.20
                 }

                ...
                 
}

my dhcpd.conf is:


ddhs-update-style none;
ignore client-updates;
share-network LOCAL{
         subnet 10.10.10.0 netmask 255.255.255.0{
         }
         subnet 127.0.0.0 netmask 255.0.0.0{
         }
         subnet 10.2.0.0 netmask 255.255.0.0{
         }
         pool{
                option routers 10.2.0.1;
                max-lease-time 66666;
                range 10.2.0.10 10.2.0.100;
         }
}



my client's ipsec.conf:

conn AU
      left=10.10.10.204
      ...
      right=10.10.10.20
      ...




my SecGW's ipsec.conf:

conn SecGW 
       left =10.10.10.20
       ...
       leftsubnet=10.1.0.0/16
       rightsourceip=%dhcp
       ...

I will appreciate your help!