Upgrade fails with error : "A problem occurred while getting data from the source vCenter Server" on Stage 1 - Connect to source appliance

Products

• VMware vCenter Server 8.0

Issue/Introduction

• While attempting to upgrade the vCenter Server Appliance(From 7.0 to 8.0), the process fails at Stage 1 - Step 3 (Connect to source appliance) with the error:
  "A problem occurred while getting data from the source vCenter server."
  
  
  
  
• On the Connect to source appliance Wizard screen of Stage1, an error occurs after click CONNECT TO SOURCE and then click NEXT.
  
  
• The following is logged in the installer log:
  %TEMP%\vcsaUiInstaller
  ex:C:\Users\Administrator\AppData\Local\Temp\2\vcsaUiInstaller\installer-YYYYMMDD-#########.log
  
  YYYY-MM-DDTHH:MM:SS.###Z - error: Could not get response for get request from url https://esxi01.example.com:443/guestFile?id=15&token=########-####-####-####-############: Error: getaddrinfo ENOTFOUND esxi01.example.com
  YYYY-MM-DDTHH:MM:SS.###Z - error: Failed to get data from url:https://esxi01.example.com:443/guestFile?id=15&token=########-####-####-####-############, error: Could not get response for get request from url https://esxi01.example.com:443/guestFile?id=15&token=########-####-####-####-############: Error: getaddrinfo ENOTFOUND esxi01.example.com
  YYYY-MM-DDTHH:MM:SS.###Z - error: Error in getting fileData for nodeType. Error: "Could not get response for get request from url https://esxi01.example.com:443/guestFile?id=15&token=########-####-####-####-############: Error: getaddrinfo ENOTFOUND esxi01.example.com"

Environment

VMware vCenter Server 8.0

Cause

There is an issue with DNS resolution of the ESXi host on the Jump Server(running the VCSA UI installer).
Jump Server cannot connect to the ESXi host(hosting the source vCenter Server VM).

Resolution

Verify DNS Server setting/Configuration and DNS resolution of ESXi host on Jump Server(nslookup ESXi-FQDN/ESXi-IP etc...).
Then Launch the VCSA UI installer and restart the upgrade process.

Additional Information

Error "A problem occurred while getting data from the source vCenter server" is encountered when upgrading the vCenter Server Appliance