Host cannot download files from VMware vCenter Update Manager patch store. Check the network connectivity and firewall setup, and check esxupdate logs for details.
Note: To permanently fix this issue, ensure the nslookup of the vCenter Update Manager server from the SSH session of ESX/ESXi host can resolve both forward and reverse IP. The DNS entry of the vCenter Update Manager server should be configured properly in the DNS server.
Based on VMware KB 2007398