Powershell - Saving downloaded file on network share - powershell

Question

The PS1 needs to download an XML file from a remote HTTP server and save it on a network share.
Summary of the script is as follows
$timer = (Get-Date -Format yyyyMMdd_hhmmss)
$storageDir = "\\10.16.99.99\what\ever\Folder"
$filename1 = "John_" + "$timer.xml"
$webclient = New-Object System.Net.WebClient
$url1 = "http://whateverURL/John.xml"
$file1 = "$storageDir\$filename1"
$webclient.DownloadFile($url1,$file1)
$source = "\\10.16.99.99\what\ever\Folder"
$target = "\\10.16.99.99\what\ever\TargetFolder"
$files = get-childitem $source -Recurse
foreach ($file in $files){
if ($file.LastWriteTime -ge (get-date).AddMinutes(-10)){
$targetFile = $target + $file.FullName.SubString($source.Length)
New-Item -ItemType File -Path $targetFile -Force
Copy-Item $file.FullName -destination $targetFile
Start-Sleep -s 3
}
}
When I run the script, I get following error through PowerShell CMD
Exception calling "DownloadFile" with "2" argument(s): "An exception occurred during a WebClient
request."
At D:\StagisEE\GlobalListing\GL_download.ps1:318 char:3
+ $webclient.DownloadFile($url1,$file1)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : WebException
Therefore I added the following lines to see what the variables are that will be used in the webClient command
Write-Host $url1
Write-Host $file1
Which gave me the following, additional, results
http://whateverURL/John.xml
\\10.16.99.99\what\ever\Folder\John_20191224_103412.xml
My question is why that the webClient is failing while the variables seems to be ok?
Or is he struggling due to the network location?