Relevant versions: Xray 2.X and Xray 3.X - Instructions and paths are for 3.X but the overall process is similar in 2.X
Xray HA requires a RabbitMQ broker per node (i.e., if you have two Xray nodes, you’ll need two RabbitMQ brokers). During setup, if the ports are not open or your machines are not communicating properly, RabbitMQ may fail to cluster correctly. This will result in messages getting lost and an unusable Xray HA.