Hello,  Thank you. There have been some reports of that KB causing issue. Server 2016 -- KB4503294   One that KB is removed, you can see one of the earlier know KBs installed causing the problem.  Regards, Don  
Heads up on KB4499177 We encountered an odd issue on some of our Win Server 2016 nodes, that connect to a PS4210 array, started this morning at about 3am. Trying to connect to some volumes (but not necessarily /all/) on the array was reporting a "Target error", and found elsewhere reports about it being an authentication failure... Takes a while to try until it hits a timeout threshold. Firmware is up to date on the array, and drivers/firmware on the hosts are also up to date.Plentiful host reboots, nothing resolved it until... Now uninstalled KB4499177 (2019-05 Cumulative Update) - rebooted - and wham, instant connectivity again. Have repeated the incident on a 2nd node in the Failover Cluster - same issue, same resolution. So, possibly Dell related, but most presumedly MS led issue on this one.Couldn't see anything relevant to this as a known issue in the KB. Other error messages reported from Windows Event Viewer:Cluster Shared Volume 'XYZ' ('XYZ') is no longer accessible from this cluster node because of error '(1460)'. Please troubleshoot this node's connectivity to the storage device and network connectivity. Event 1: Unexpected failure. Error code: 48F[NAME] Event 43: Target failed to respond in time for a login request. and from Group Manager:iSCSI session to target 'XYZ from initiator 'XYZ' was closed. iSCSI initator connection failure. No response on connection for 6 seconds. iSCSI login to target 'XYZ' from initiator 'XYZ' failed for the following reason:Requested target not found.
iSCSI connection failures after KB4499177