Re: Remote User VPN can't access site-to-site VPNs

 is right that the L2TP ip address range used might break connectivity.

However, simply adding routes might not work:  On classic ipsec vpn, source and destination networks are manually configured. 

Only when using VTI mode, adding a route suffices.  (or just advertise the L2TP network in routing protocol like OSPF)