We use ftpPublisher with 

continueOnError: false, failOnError: true

so we would expect that the step fails when an error occurs during publishing. 

However, we get 

ERROR: Exception when publishing, exception message [Connection refused (Connection refused)]

but the step does not fail but ends with SUCCESS. 

This is a problem, because other jobs fail that depend on the published artifacts, and the actual cause goes unnoticed. Instead, we have to check the console logs manually.

Is there anything else that needs to be configured? Otherwise, I'd say this is a bug.