A bit of and odd one this but I am casting my net wider. We have a VPN running between two Vigor routers and we had a NAS running on truenas core with SMB shares. All worked well. We have recently migrated from truenas core to scale and the smb shares are no longer available  over the VPN network. Any pointers would be useful. All other resources including another NAS  (not a truenas) are all available.

No experience with TRUENAS, but does your new NAS system possibly have any kind of built-in firewall or access control, which is denying access from the remote LAN (likely a different subnet)?

Hi no firewall in Truenas scale. There is no visibility of the NAS over the VPN

When you say 'no visibility' - can you ping the NAS over the tunnel?

Can you post any further details about your configuration, (IP addressing, etc)?

Hi can ping it on local network which is 172.20.1.200 but not over the vpn local network there is 172.16.1. xxx The two draytek routers are on 172.20.1.1 and the other one is on 172.16.1.1

To clarify, do you mean your NAS is on 172.20.1.0, and your remote network is 172.16.1.xxx?

So when trying to access the NAS over the VPN, your PC has an address from 172.16.1.xxx?

If that is the case: I believe TrueNAS Scale uses Kubernetes, and 172.16.0.0/16 is the default network used internally by Kubernetes. TrueNAS is likely routing responses to that network rather than back to your PC over the VPN.