OfficeDevPNP Add-PnPFile error folder already exists while looping through directories

Made few corrections in your script to work. Below is the updated script.

$sourcePath = $PSScriptRoot; # 1.Don't forget to add  "\" at end of $PSScriptRoot String value 
#$topSPOFolder = "SiteConfigurations/_PSI_Gestapeld";
$topSPOFolder = "Bieb1/_PSI_Gestapeld";
# install pnp powershell..?
#Install-Module SharePointPnPPowerShellOnline;
# connect to spo online; TODO: use appid and appsecret
Connect-PnPOnline -Url $makeUrl -UseWebLogin;
# foreach (updated or new?) file in git project
$fileNames = Get-ChildItem -Path $sourcePath -Recurse -Include *.json,*.xml;
$fileNames = Get-ChildItem -Path $sourcePath -Recurse ;
foreach($aFileName in $fileNames)
{
if($aFileName.GetType().Name -ne "DirectoryInfo") 
   {
     $filepath= [System.IO.Path]::GetDirectoryName($aFileName.FullName)
     $Urlpath= ($filepath.Replace($sourcePath, ''));
     $foldername=$Urlpath.Replace("/","\");  # 2."\","/" was changed
     $fn=$topSPOFolder+"\"+$foldername; # 3. "\" Added 
     Add-PnPFile -Path $aFileName.FullName -Folder $fn;
     $fn=$null
   }

}