Get-WebExceptionBody.ps1

function Get-WebExceptionBody
{
  param(
    [int]$Last
  )

  if(-not $PSBoundParameters.ContainsKey('Last')){
    $Last = 1
  }

  $ex = $Error |? { $_.Exception -is [System.Net.WebException]} |Select -First $Last
  if($ex){
    $resp = $ex.Exception.Response
    $respstream = $resp.GetResponseStream()
    $respstream.Position = 0
    [System.IO.StreamReader]::new($respstream).ReadToEnd()
    $respstream.Dispose()
  }
}