Cluster: Not Reachable On UDP Port 3433
KB ID 0001621 Problem Seen on a Microsoft Hyper-V failover cluster (Server 2019); Network Interfaces {Node-Name} {Interface-Name} and {Node-Name} {Interface-Name} are on the same cluster network, yet address {IP-Address} is not reachable from {IP-Address} using UDP port 3433 Solution I’ve seen this error before, and usually you just need to disable the firewall or open UDP port 3433 and then re-validate the cluster (job done)....