Site to Site VPN routing problem

I am using a Site to site VPN on 2 x Slate AX (GL-AXT1800).
I am problems routing both ways.

I can connect from Main Node to Node 1, but not the other way. I can ping both gateways, and have tried static routes to the destination subnets (both in the Slates and in my clients).

Any help would be appreciated.

Are you using the Goodcloud managed solution? Or manual setup.