If Kerberos is enabled.Try the below steps:- 1)ambari-server setup-security 2)Enter choice, (1-5): 3 3)Enter ambari server's kerberos principal name (ambari@EXAMPLE.COM): ambari-serve-xxx@REALM.COM 4)Enter keytab path for ambari server's kerberos principal:/etc/security/keytabs/ambari.server.keytab 5)Restart ambari server: ambari-server restart. Do upvote if this article helped. Ref: https://docs.hortonworks.com/HDPDocuments/HDP3/HDP-3.1.0/authentication-with-kerberos/content/set_up_kerberos_for_ambari_server.html ... View more

Did you make a principle and a keytab for this nifi ? Is the node(where standalone nifi is installed) added in the cluster ? Can you share the kerberos logs and Nifi logs ! ... View more