I talked to Mike on the phone.  The issue what that the auth service was blocked on all 4 nodes.  We restarted it with:  sudo kill `pidof authsvc`  And logins now work to the portal.  We'll work on the cyberduck issue as next.
I have a four node ECS 3.0 cluster that has been working fine for three weeks.  Recently, attempting to log into the Web UI from all four nodes returns the same error message:   Unable to connect to the service. Service(s) are unavailable, try again later.    S3 connectivity has been intermittent for a time during this UI issue, but it seemed to recover and has been continuing to service application needs. And since this login problem occurs against each of the four nodes, I question whether there's a single log to glean more information from.  ECS service log locations / /opt/emc/caspian/fabric/agent/services/object/main/log  Thoughts?
ECS 3.0 Community Edition Web UI