Error: Amazon 500150 - Error Setting/Closing Connection: Connection Refused

Issue

Syncs are failing intermittently in the sync history chart within the connector status page. One of the following error messages appears:

• SocketTimeoutException: Read timed out.
• [Amazon 500150] Error setting/closing connection: Connection refused.
• java.net.ConnectException: Connection timed out (Connection timed out).

Environment

Redshift destination (connecting with an SSH Tunnel)

Resolution

Increase the concurrent connection limit on your SSH Tunnel server.

Cause

If you are using sshd, the MaxSessions default limit is 10.