I had the same problem when I tried to create output port in sub-processor group.
I have to create output port in root processor group and link from sub-processor group to this port.
I've configured my nifi to use 2 Way SSL for user authentication, without cluster.
I want to create an output port to send data to Spark.
Nifi complains that "output connection for port is not defined".
How, and where, do I configure that port? I did not find any information about this configuration.
Thanks for any pointer.