Client VPN from SG1100 to SG2100 Pending

[Bert 0]

I would like to have a router to router VPN connection between an SG1100 (DHCP behind double NAT) to an SG2100 (static ip). So I created an OpenVPN server on the 2100 setting it for user auth and a locally generated TLS key. I then set up a client on the 1100 pointing at the 2100's public ip address with User Auth and the same TLS key as on the 2100. But, when I run the client, the status remains "Waiting for response from peer" and both local address and remote Host remain at "(pending)" and the virtual address is blank.

What did I do wrong and how do I troubleshoot this? The logs don't say very much at either end so I'm not sure where I should start.

As an aside, is it possible to have a true Site-to-Site VPN (bidirectional) configured in this scenario?

Thanks