L2TP IPSEC VPN through pfSense

At work we use a Meraki MX64 firewall with client VPN (i.e. L2TP IPSEC PSK VPN). I am not able to connect to it through my pfSense box. Does anyone have a suggestion on what to look at to get this working? I had to deploy the OpenVPN Access Server appliance to get a connection for now.