Let us know if you have fixed the ConnectionRefused Error to Master1 on Port 16000. As @rki_ mentioned, Review the HMaster Logs to confirm the reasoning for ConnectionRefused. Few possible scenarios being Port 16000 is being used by any other Service Or, "master1" isn't correctly being mapped as per DNS Or, Port 16000 may be blocked. Based on the HMaster Logs, We may offer further review.
As such, If the Issue persists, Share the HMaster Logs covering the concerned Stacktrace as well. If the Issue has been resolved, We shall appreciate if you can share the details into the Cause & Fix applied.