This error usually indicates that you are successfully connecting to your SAN target, but the SAN disk you are trying to access is not available.

Things you can try:

• Check that the SAN disk is online and enabled.
• If you have specified a LUN as part of an iSCSI root path, check that you have used a correctly formatted hexadecimal (not decimal) value.
• Note that the default configuration when Linux is the target is for the disk to be LUN 1. For example, use “iscsi:iscsi.example.com:::1:iqn.1992-01.com.example.iscsi:target” instead of “iscsi:iscsi.example.com::::iqn.1992-01.com.example.iscsi:target”. On your Linux iSCSI target, “tgtadm –lld iscsi –op show –mode target” will show you details of each target.
• If your target is Linux-IO (LIO/targetcli) the default LUN number is 0 instead of 1.

See also error 0x1d704239.