The storage node. The password was the same in the UI under the new storage node and .fogsettings but setting it for the local user using ‘passwd fog XXXXX’ is what did the trick.

FWIW, I was having the same issue until I set the password of the ‘fog’ user on the second node to what was displayed in /opt/fog/.fogsettings. Sync began immediately after I restarted the replicator service.