I have a fairly recent three node HCI setup running 4.2.5.  I've recently updated hosted engine to the latest version (including yum updates).  When I check for host updates through the engine gui I get the following error for all three of my hosts:

Failed to check for available updates on host XXXXX with message 'Failed to run check-update of host 'XXXXXX'.'.

The engine.log shows not much more detail:

2018-08-20 14:26:28,396-03 ERROR [org.ovirt.engine.core.bll.host.HostUpgradeManager] (EE-ManagedThreadFactory-commandCoordinator-Thread-2) [4400c1d5-5412-4f1a-9c25-40fe0fb53295] Failed to run check-update of host 'XXXXX'.
2018-08-20 14:26:28,397-03 ERROR [org.ovirt.engine.core.bll.hostdeploy.HostUpdatesChecker] (EE-ManagedThreadFactory-commandCoordinator-Thread-2) [4400c1d5-5412-4f1a-9c25-40fe0fb53295] Failed to check if updates are available for host 'Orchard2' with error message 'Failed to run check-update of host 'XXXXX'.'
2018-08-20 14:26:28,411-03 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (EE-ManagedThreadFactory-commandCoordinator-Thread-2) [4400c1d5-5412-4f1a-9c25-40fe0fb53295] EVENT_ID: HOST_AVAILABLE_UPDATES_FAILED(839), Failed to check for available updates on host Orchard2 with message 'Failed to run check-update of host 'XXXXX'.'.

Yum seems to run ok manually on the server (although not showing any updates available). 

Here is node and yum info/output from one of my hosts:

 nodectl check; nodectl info; yum update
Status: OK
Bootloader ... OK
  Layer boot entries ... OK
  Valid boot entries ... OK
Mount points ... OK
  Separate /var ... OK
  Discard is used ... OK
Basic storage ... OK
  Initialized VG ... OK
  Initialized Thin Pool ... OK
  Initialized LVs ... OK
Thin storage ... OK
  Checking available space in thinpool ... OK
  Checking thinpool auto-extend ... OK
vdsmd ... OK
layers:
  ovirt-node-ng-4.2.5.1-0.20180806.0:
    ovirt-node-ng-4.2.5.1-0.20180806.0+1
bootloader:
  default: ovirt-node-ng-4.2.5.1-0.20180806.0+1
  entries:
    ovirt-node-ng-4.2.5.1-0.20180806.0+1:
      index: 0
      title: ovirt-node-ng-4.2.5.1-0.20180806.0
      kernel: /boot/ovirt-node-ng-4.2.5.1-0.20180806.0+1/vmlinuz-3.10.0-862.9.1.el7.x86_64
      args: "ro crashkernel=auto rd.lvm.lv=onn_orchard0/swap rd.lvm.lv=onn_orchard0/ovirt-node-ng-4.2.5.1-0.20180806.0+1 rhgb quiet LANG=en_CA.UTF-8 img.bootid=ovirt-node-ng-4.2.5.1-0.20180806.0+1"
      initrd: /boot/ovirt-node-ng-4.2.5.1-0.20180806.0+1/initramfs-3.10.0-862.9.1.el7.x86_64.img
      root: /dev/onn_orchard0/ovirt-node-ng-4.2.5.1-0.20180806.0+1
current_layer: ovirt-node-ng-4.2.5.1-0.20180806.0+1
Loaded plugins: enabled_repos_upload, fastestmirror, imgbased-persist, package_upload, product-id, search-disabled-repos, subscription-manager, vdsmupgrade
This system is not registered with an entitlement server. You can use subscription-manager to register.
Loading mirror speeds from cached hostfile
 * ovirt-4.2-epel: ewr.edge.kernel.org
No packages marked for update
Uploading Enabled Repositories Report
Loaded plugins: fastestmirror, product-id, subscription-manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
Cannot upload enabled repos report, is this client registered?

Thanks!