Aggressive antivirus software (Avast, Norton, McAfee) or Windows Defender can block Droid4X from generating or accessing download URLs.
Search for “Droid4X OVA file” on archive.org or Android emulator forums. Place the file in the cache folder with the expected name. how to fix droid4x request download url failed work
After applying a solution, confirm success by: Aggressive antivirus software (Avast