Receiving error on iscsi device: "connectionX:0: detected conn error" in RHEL

Issue

- iSCSI LUN from external storage is shared in two different servers. Following error messages are seen in /var/log/messages file related to iscsi LUNs.

Apr  1 11:43:11 hostname kernel: connection36:0: detected conn error (1020)
Apr  1 11:43:11 hostname kernel: connection34:0: detected conn error (1020)
Apr  1 11:43:11 hostname kernel: connection33:0: detected conn error (1020)
Apr  1 11:43:12 hostname iscsid: Kernel reported iSCSI connection 18:0 error (1020 - ISCSI_ERR_TCP_CONN_CLOSE: TCP connection closed) state (3)
Apr  1 11:43:12 hostname iscsid: Kernel reported iSCSI connection 20:0 error (1020 - ISCSI_ERR_TCP_CONN_CLOSE: TCP connection closed) state (3)
Apr  1 11:43:12 hostname iscsid: Kernel reported iSCSI connection 30:0 error (1020 - ISCSI_ERR_TCP_CONN_CLOSE: TCP connection closed) state (3)

• multipath paths failed after kernel reported "connectionX:0: detected conn error (1020)" and the server became unresponsive
• iscsi connections failed with a "conn error"
• What is causing my iscsi connections to report an error?