@Sri Bet When a node attempts to join an existing cluster there are 3 files that are checked to make sure they match between the node connecting and the cluster: 1. flow.xml.gz (Contains everything you have configured/added via the NiFi UI.) 2. users.xml (Contains all users added via the NiFI UI. This file will not exist if you are not using NiFi's default file based authorizer. Also will not exist if NiFi is not running secured) 3. authorizations.xml (Contains all authorization policies which have been granted to above users added via the NiFI UI. This file will not exist if you are not using NiFi's default file based authorizer. Also will not exist if NiFi is not running secured) - I am not sure why one of your nodes had a mismatch in your authorizations.xml file. Perhaps while this node was not in the cluster a new policy was granted to a user? - Deleting the users.xml and authorizations.xml files is not the best resolution. When these files do not exist, NiFi will create on the basic authorizations for the initial admin identity and nodes defined in the authorizers.xml file. deleting these files will result in loss of any other authorizations that ay have been granted later. - The best fix is to copy the users.xml and authorizations.xml from another node to the node having issues. - Thank you, Matt ... View more