User Sync Problem on connection setup

When I try to get it set up the system reports there was a user synchronization problem.

We are trying to have a master site, developers.zone with sub sites, these for now; jquery.developers.zone, bootstrap.developers.zone and knockout.developers.zone. We want all four of these in sync for users. We would like them to be able to set up on any site and sync back out to the others. I saw the docs mention a way to automate that.