This is a subset of events relating to iSCSI storage.
Login to iSCSI target failed. Target returned login error.
There is an issue with the connection or configuration of this iSCSI storage.
See the event description for more detailed information specific to this event. Check for network configuration and availability. Try a rescan of the storage adapters for this host.
For more troubleshooting information see the VMware KB article Troubleshooting ESX and ESXi connectivity to iSCSI storage arrays using software initiators.