The issue above, specifically also containing error: java.lang.RuntimeException: Cannot create negative queue size seems to have been solved in Nifi v15.1 or v16!  See [NIFI-9433] Load Balanced Connections hangs / log "Cannot create negative queue size" - ASF JIRA (apache.org)   Myself, I  have an issue in the same high-level error "ConnectionLoadBalanceServer Failed to communicate with Peer node" , but a different (root)cause ( which I'm not sure yet how it is  caused , but must be related to network, our docker-swarm multi-node deployment OR a resource bottleneck): ... ERROR [Load-Balanced Client Thread-7] o.a.n.c.q.c.c.a.n.NioAsyncLoadBalanceClient Failed to communicate with Peer nifi2:8443 java.net.SocketTimeoutException: Timed out waiting for Peer nifi2:8443   ... View more