Current documentation for setting up NiFi & SSL is working until you try to access NiFi UI in which case you get "Access Denied" exception. And also Kylo services can't access NiFi. The reason is wrong setup of Initial Admin Identity in /opt/nifi/data/conf/authorizers.xml file.
NiFi & SSL part of documentation should be updated in step 9 (update of /opt/nifi/data/conf/authorizers.xml file):
in property Initial Admin Identity there should be a space after comma and before OU in the value to be the same as in step 6, i.e. CN=kylo, OU=NIFI
remove duplication of Initial Admin Identity property (remove one with no value)
Pull request accepted, can be closed