If you are still using Windows 2008 for vCenter Server. You may see ESXi hosts lost connection back and forth on vCenter Server after recent Windows pathing. It’s not something like a heartbeat lost for a few seconds. ESXi can takes minutes to back online.

You can see similar logs in vpxd.log:

2018-08-03T09:24:23.337-04:00 error vpxd[20160] [Originator@6876 sub=HttpConnectionPool-000000] [ConnectComplete] Connect failed to <cs p:00000000200ed300, TCP:XXXXXXXXXXXXXXXX:443>; cnx: (null), error: class Vmacore::SystemException(Only one usage of each socket address (protocol/network address/port) is normally permitted)

2018-08-03T09:24:23.337-04:00 error vpxd[06332] [Originator@6876 sub=Vmomi opID=HB-host-28@307067-1d257f9c] [VpxdClientAdapter] Got vmacore exception: Only one usage of each socket address (protocol/network address/port) is normally permitted


2018-08-03T09:24:23.338-04:00 error vpxd[06332] [Originator@6876 sub=Vmomi opID=HB-host-28@307067-1d257f9c] [VpxdClientAdapter] Backtrace:


–> [backtrace begin] product: VMware VirtualCenter, version: 6.0.0, build: build-3634793, tag: vpxd

–> backtrace[00] vmacore.dll[0x001C599A]

–> backtrace[01] vmacore.dll[0x0005C8BF]

–> backtrace[02] vmacore.dll[0x0005DA0E]

That’s because your Windows server installed one of following patches.

July 10, 2018—KB4338818 (Monthly Rollup)

July 10, 2018—KB4338823 (Security-only update)

The fixes are the following.

If you installed KB4338818, please install July 18, 2018—KB4338821 (Preview of Monthly Rollup)

If you installed KB4338823, please install Improvements and fixes – Windows 7 Service Pack 1 and Windows Server 2008 R2 Service Pack 1 (KB4345459)