@JamesZhang  Certainly a challenging issue you have here.  The shared output all points to good certificates, but gets you no closer to why the mutualTLS exchange between your two Nifi nodes is no yielding a successful mutual TLS handshake. I guess I would start by looking at the configuration of NiFi on both nodes to make sure configurations in the nifi.properties files on both nodes match.  Verify that both nodes NiFi's are using same Java version. You may need to look at the network traffic between both nodes as well.  Is there some device (load balancer, firewall, etc) between those nodes on the network that may be interfering with the certificate exchange. Matt ... View more