Cannot connect to L2TP Server – Edge Router Lite

[xrs]

Dear geniuses of Overclockers. Before I head over to the Ubiquiti forums, I was wondering if anybody could possibly help me. I am having trouble setting up my L2TP VPN server on my Edge Router Lite.
I have managed to setup the PPTP VPN Server using a dynamic address. When I try to connect to my L2TP Server I get the message: "The L2TP-VPN server did not respond."

Here is the config I used: (sanitised of course)
Configure
Set vpn ipsec ipsec-interfaces interface eth1
Set vpn l2tp remote-access dhcp-interface eth 1
Set vpn ipsec nat-traversal enable
Set vpn ipsec nat-networks allowed-network 0.0.0.0/0
Set vpn l2tp remote-access client-ip-pool start 192.168.1.145
Set vpn l2tp remote-access client-ip-pool stop 192.168.1.149
Set vpn l2tp remote-access dns-servers server-1 8.8.8.8
Set vpn l2tp remote-access dns-servers server-2 8.8.4.4
Set vpn l2tp remote-access authentication mode local
Set vpn l2tp remote-access authentication local-users username user password test1
Set vpn l2tp remote-access ipsec-settings authentication mode pre-shared-secret
Set vpn l2tp remote-access ipsec-settings authentication pre-shared-secret secretphrase
Set vpn l2tp remote-access ipsec-settings ike-lifetime 3600
Set vpn l2tp remote-access mtu 1492
Commit
Show vpn l2tp remote-access
save

Have I made an obvious error?
Any help would be greatly appreciated. Please feel free to ELI5!