Posting here in case it helps anyone. I setup Ghost with the new Docker Preview and everything has been working mostly great except the “Social Web” Network tab which constantly just gave a “Site not configured correctly”.
There weren’t any overt errors in the docker logs for the container other than complaints about no webhook_secret being available. I’ve spent way too much time trying to figure that out. In the course of trying to figure it out though I started noticing that the logs seemed “off”. Looking more closely they were 10 minutes off. HyperV time drift off. 
I installed NTP on the VM and got it setup and restarted the docker container and viola! the network tab worked.
SO…all that to say…if you are getting errors with the social web component but everything else is working fine - check system time.