I have completed this in the format below before and it has worked fine... here is the config (basic of the broken section for LNS):
set services l2tp tunnel-group lns-test service-device-pool lns
set access address-assignment pool POOL family inet network 192.168.85.0/24 set access address-assignment pool POOL family inet range lns low 192.168.85.1 set access address-assignment pool POOL family inet range lns high 192.168.85.254
Now when I try and commit the whole config I get the following error:
'service-device-pool lns' referenced service device pool must be defined
Now, I understand that I have configured a pool called POOL but it has the range labelled as "lns" which is normally called within the group.