A depot is inaccessible or has invalid contents. Make sure an official depot source is used and verify connection to the depot.

No patch builds are listed in the Updates tab of the Lifecycle Manager and there are no firewalls or network-level blocks preventing access.
In the vCenter Server /var/log/vmware/vmware-updatemgr/vum-server/vmware-vum-server.log, entries similar to the following are observed:
YYYY-MM-DD HH:MM:SS warning vmware-vum-server[59362] [Originator@6876 sub=VumVapi::Lib::Utils] [EmbeddedPyServiceProvider 472] Connecting to https://hostupdate.vmware.com/software/VUM/PRODUCTION/addon-main/vmw-depot-index.xml failed, err: curl_easy_perform() failed: cURL Error: Could not resolve hostname, Could not resolve host: hostupdate.vmware.comYYYY-MM-DD HH:MM:SS warning vmware-vum-server[59362] [Originator@6876 sub=VumVapi::Lib::Utils] [EmbeddedPyServiceProvider 425] Failed 10 times when connecting online depot https://hostupdate.vmware.com/software/VUM/PRODUCTION/addon-main/vmw-depot-index.xmlYYYY-MM-DD HH:MM:SS error vmware-vum-server[59362] [Originator@6876 sub=ServiceProvider] [EmbeddedPyServiceProvider 1570] At least one online depot is not accessible: https://hostupdate.vmware.com/software/VUM/PRODUCTION/addon-main/vmw-depot-index.xml, https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml, https://hostupdate.vmware.com/software/VUM/PRODUCTION/iovp-main/vmw-depot-index.xml, https://hostupdate.vmware.com/software/VUM/PRODUCTION/vmtools-main/vmw-depot-index.xmlYYYY-MM-DD HH:MM:SS error vmware-vum-server[59362] [Originator@6876 sub=com.vmware.vcIntegrity.lifecycle.SyncDepotsTask] [SyncDepotsTask 221] Failed to sync depots. Merged depot content is invalid: Error:--> com.vmware.vapi.std.errors.error--> Messages:--> com.vmware.vcIntegrity.lifecycle.depotContent.ValidationError<A depot is inaccessible or has invalid contents. Make sure an official depot source is used and verify connection to the depot.>-->
Not Connected'.VMware vCenter Server 8.x
This issue can occur due to any of the following reasons:
http://vibsdepot.example.com/index.xml or the default Life cycle manager URLs https://hostupdate.vmware.com are enabled but Not Connected as a download source.This leads to errors or failures when attempting to fetch VIBs or updates from that repository.
https://hostupdate.vmware.com) marked as "Not Connected" from the list and try to resync.If the issue is related to a VMware depot, refer to the following articles: