Quantum Spark 1600 cluster problem

[StevePearson]

I'm just clustering a pair of 1600's and have hit a problem.

I've got the LAN and WAN and Cluster addresses all set correctly, everything appears to work fine except the client VPN, the clients are unable to connect.

It's worth saying that the primary box has been live for months, no issues, including the VPN.

What I did was changed the LAN and WAN IP addresses of the live box, set new LAN/WAN addresses on the new secondary box (although I haven't connected this yet), and then created the cluster using the original LAN/WAN IP addresses to ensure there are no changes for the users (internal or external).

When I check the VPN Blade control page, it shows the VPN is using a static IP but it's using the WAN address of the gateway rather than the cluster, so i'm thinking that this is the issue?

As a test, if I create a new site on the client, but using the gateway IP, that also doesn't connect, you get the login screen but it does not accept the password. (so same effect)

I can't find anything about this anywhere, and as it's not an unusual situation i'm hoping someone can advise please?

Firmware is R81.10.10

Thanks.