I just recently imported a certificate chain into the keystore that NiFi points to, on 3 NiFi nodes, call them node1, node2 and node3. The truststore.jks file so far has been unedited.   Testing out the SSL handshakes between nodes, I get:   SSL handshake has read 4537 bytes and written 495 bytes ... return code: 0 (ok)     Executed from node 2 requesting node 1 (using the same port configured in NiFi SSL settings in Ambari)   Similarly other combinations also were successful, (node1 -> node2, node3 -> node1, etc.)   However, when after the certificate import and then restarting NiFi, trying the NiFi UI, it shows that the cluster has been disconnected.   Furthermore, it shows that the SSL handshakes are failing:   Attempt to contact NiFi Node https://node2:port/nifi did not complete due to exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target Attempt to contact NiFi Node https://node3:port/nifi did not complete due to exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target Attempt to contact NiFi Node https://node1:port/nifi did not complete due to exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target.   What is going on here? Why isn't the SSL handshake working through NiFi? ... View more