It seems like you are facing a connectivity issue. The error message you quoted suggests that your application is unable to reach the Master Aggregator node. It is crucial to ensure that all nodes are consistently reachable within a SingleStore cluster for HA and load-balancing to operate as expected.SingleStore’s High Availability(HA) is designed to tolerate the failure of individual nodes within the topology, but not the failure of the entire Master Aggregator.
The Master Aggregator is a critical component for maintaining and coordinating the cluster state. If you have stopped the Master Aggregator node, your connections will still be disrupted unless you take further steps to recover.
If there is a need to stop or shut down the Master Aggregator for maintenance or other reasons, SingleStore supports promoting a Child Aggregator to be the new Master (Setup for Replication Database Between Cluster). This can be done using the AGGREGATOR SET AS MASTER command. This will maintain availability of the cluster even if the original Master Aggregator is down.
If you experience more issues, I would recommend filing a support ticket.