VMware vSphere Update Manager had an unknown error. Check the events and log files for details.

I'm having trouble scanning for updates on vsphere 6.5. I get the message in the thread subject each time I try to scan for updates. I've also taken a look at /var/log/vmware/vmware-updatemgr/vum-server/vmware-vum-server-log4cpp.log:

[CODE]

[2018-08-27 13:10:50:011 'HostUpdateDepotManager' 140487137134336 ERROR]  [patchDepotManager, 663] Error in download and parse metadata: Failed to download file: https://hostupdate.vmware.com/software/VUM/PRODUCTION/csco-main/esx/csco/csco-VEM-5.5.0-notifications.zip\nexception when downloading metadata: Failed to download metadata zip file: https://hostupdate.vmware.com/software/VUM/PRODUCTION/csco-main/esx/csco/csco-VEM-5.5.0-notifications.zip

[2018-08-27 13:10:50:011 'VciCheckNotificationTask.CheckNotificationTask{11382}' 140487137134336 ERROR]  [vciCheckNotificationTask, 524] There was an error downloading ESX notification from: https://hostupdate.vmware.com/software/VUM/PRODUCTION/csco-main/csco-depot-index.xml, error: Failed to download file: https://hostupdate.vmware.com/software/VUM/PRODUCTION/csco-main/esx/csco/csco-VEM-5.5.0-notifications.zip\nexception when downloading metadata: Failed to download metadata zip file: https://hostupdate.vmware.com/software/VUM/PRODUCTION/csco-main/

[/CODE]

or this:

[CODE]

[2018-08-27 13:10:02:244 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 1349] SerializeToVimFault fault: (integrity.fault.VcIntegrityFault) {    faultCause = (vmodl.MethodFault) null,     faultMessage =    msg = "" } Converted fault: (vim.fault.ExtendedFault) {    faultCause = (vmodl.MethodFault) null,     faultMessage =,     faultTypeId = "com.vmware.vcIntegrity.VcIntegrityFault",     data = (vim.KeyValue) [       (vim.KeyValue) {          key = "faultCause",           value = ""       },        (vim.KeyValue) {          key = "faultMessage",           value = ""       }    ]    msg = "" } [2018-08-27 13:10:02:244 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 1621] Description updated [2018-08-27 13:10:02:247 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 1362] VciTask { id: ScanTask{11383}, type: com.vmware.vcIntegrity.ScanTask }: Setting VC task state to: error [2018-08-27 13:10:02:252 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 190] Delete VC task from database: task-11207

[2018-08-27 13:10:02:244 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 1621] Description updated

[2018-08-27 13:10:02:247 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 1362] VciTask { id: ScanTask{11383}, type: com.vmware.vcIntegrity.ScanTask }: Setting VC task state to: error

[2018-08-27 13:10:02:252 'VciScanTask.ScanTask{11383}' 140487130212096 INFO]  [vciTaskBase, 190] Delete VC task from database: task-11207

[/CODE]

I'm not sure what I'm supposed to be looking for.

Any ideas what's going on? What other info should I be searching for?