usp_ipc_client_reconnect messages in syslog

Hi, I have a cluster on the SRX 3600. RG0 and RG1 active on different nodes.
In syslog began to appear messages
FW-node1 node1.fpc7.pic0 usp_ipc_client_reconnect: failed to connect to the server: Connection refused (61)
FW-node1 node1.fpc8.pic0 usp_ipc_client_reconnect: failed to connect to the server: Connection refused (61)
FW-node1 node1.fpc9.pic0 usp_ipc_client_reconnect: failed to connect to the server: Connection refused (61)
FW-node1 node1.fpc10.pic0 usp_ipc_client_reconnect: failed to connect to the server: Connection refused (61)
Perhaps someone can explain the reason for these messages.
Thanks