Got this error just today and couldn’t figure out why. I was trying to copy from my management server to a test VM with no network connectivity, and was receiving the following error:
Copy-VMGuestFile : 5/01/2017 11:47:40 AM Copy-VMGuestFile The remote server returned an error: (403) Forbidden. At line:1 char:1 + Copy-VMGuestFile -Source "REDACTED" -Destination " ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : NotSpecified: (:) [Copy-VMGuestFile], ViError + FullyQualifiedErrorId : Client20_VmGuestServiceImpl_UploadFileToGuest_UploadError,VMware.VimAutomation.ViCore.Cmdlets.Commands.CopyVMGuestFile
My privileges and network connectivity to vCenter and the ESXi hosts was looking good. Until I tripled checked my network port access to the ESXi host.
I was missing port 903 from the management server to the ESXi host the VM was sitting on. Opening that up allowed me to execute the command.
Check your ports people.