Can't seem to get L2TP working on my ERPoE with v1.8

Hi, absolute newbie here trying to get started with my ERPoE here. I have v1.8 installed on it. I used the Load Balancing wizard with main WAN on eth0, failover WAN on eth1, and a single switch for eth2, eth3 and eth4; the DHCP server is assigning 10.0.1.2-10.0.1-240 for this switch. I also created a custom username and password. Currently the ERPoE is behind my main router while I was trying to get it up and running and has been assigned a static IP of 10.0.0.174. 

I have tried for about three days to get L2TP working following the guides here and here with no success; I've reset the device about 18-20 times at this stage trying desperately to get it working in case I was copy/pasting instructions incorrectly. 

However, both my Macs and my iPhones error out with a message that reads "The L2TP-VPN server did not respond. Try reconnecting. If the problem continues, verify your settings and contact your Administrator." Obviously, I have tried reconnecting many many many many many times; the only thing that happens is the stat for WAN_LOCAL Allow IKE (port 500) goes up by 1 packet every time I try to connect.

Can anyone help? I do not understand what is breaking and there's no logs anywhere that suggest why this is happening. Here is the VPN configuration section:

user@edgerouter# show vpn
 ipsec {
     auto-firewall-nat-exclude disable
     ipsec-interfaces {
         interface eth0
     }
     nat-networks {
         allowed-network 0.0.0.0/0 {
         }
     }
     nat-traversal enable
 }
 l2tp {
     remote-access {
         authentication {
             local-users {
                 username sanitizedName {
                     password sanitizedPassword
                 }
             }
             mode local
         }
         client-ip-pool {
             start 10.0.1.241
             stop 10.0.1.245
         }
         dhcp-interface eth0
         dns-servers {
             server-1 8.8.4.4
             server-2 8.8.8.8
         }
         ipsec-settings {
             authentication {
                 mode pre-shared-secret
                 pre-shared-secret sanitizedPreSharedSecret
             }
             ike-lifetime 3600
         }
         mtu 1492
     }
 }

On the Mac, there's several repeating segments as follows over a five second time period:

racoon[9576]: IKE Packet: receive failed. (Information message).
racoon[9576]: IKE Packet: transmit success. (Phase 1 Retransmit).
racoon[9576]: ignore information because the message is too short
racoon[9576]: ignore information because the message is too short

Please let me know if there's something else you need to see.