Can you share your configuration of QueryDatabaseTable and its DBCP Controller Service? Also you should be able to find more information about those bulletins/errors in logs/nifi-app.log, please paste in the relevant stack trace as it will help determine the issue you're having.
Hey @Nikhil Vemula!
I'm not sure about your error, but are you able to connect to the mysql from your Nifi host?
telnet <mysql> port
And could you share your configs from querydatabse processor and see if there's more detail on nifi's log.
PS: Did you set any DBCPConnectionPool at the controller service?
Hope this helps!