HttpClient Errors upon loading StreamContent() while FileOpenRead() Works

Question

I'm attempting to move pdf files between two web services. To start, I successfully downloaded a file form the source service to local storage using await httpClient.GetStreamAsync(varPdfUrl) and then uploaded it to the destination service using File.OpenRead() which is commented out below. When I attempt to use await httpClient.GetStreamAsync(varPdfUrl) to load the StreamContent directly I get the following error.

Error Message: System.Net.Http.HttpRequestException: Error while copying content to a stream. ---> System.IO.IOException: Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host..

 var httpClient = new HttpClient();
 var request = new HttpRequestMessage(HttpMethod.Post, uploadResponse.url);
 var content = new MultipartFormDataContent();

  // Populate MultipartFormDataContent 
  content.Add(new StringContent(uploadResponse.fields.key), "key");
  content.Add(new StringContent(uploadResponse.fields.ContentType), "Content-Type");

  // Add File Stream
  string fileName = drawingTemp.ProjectNumber + "-" + drawingTemp.Title + ".pdf";

  //string localPath = @"C:\... \CMP\Drawing Downloads\";
  //var fileSteamLocalFile = new StreamContent(File.OpenRead(localPath + fileName));
  //content.Add(fileSteamLocalFile, "file", fileName);

   var fileSteam = new StreamContent(await httpClient.GetStreamAsync(drawingTemp.PdfUrl));
   content.Add(fileSteam, "file", fileName );

   content.Add(new StringContent(uploadResponse.uuid), "uuid");

   try
       {
           //Upload File to AWS
            request.Content = content;
            var responseUploadFileMsg = await httpClient.SendAsync(request);
       }
     

I guess all StreamContent objects are not created equal... please advise. Thanks!

UPDATE

I'm still unable to populate StreamContent with httpClient.GetStreamAsync() but as a work around I'm able to write the file to a project folder "wwwroot/Files" and then use File.OpenRead() to read the file and populate StreamContent. I would still appreciate any ideas as to why populating StreamContent directly with httpClient.GetStreamAsync() throws the error listed above.

    var httpClient = new HttpClient();
    var request = new HttpRequestMessage(HttpMethod.Post, uploadResponse.url);
    var content = new MultipartFormDataContent();

    // Add File Stream
    string fileName = drawingTemp.ProjectNumber + "-" + drawingTemp.Title + ".pdf";
    Stream fileSteam = await httpClient.GetStreamAsync(drawingTemp.PdfUrl);

   // Convert Stream to File and save temporarily to wwwroot/Files 
   string writeFullPath = @"wwwroot\Files\" + fileName;
                    
   if (!File.Exists(writeFullPath))
   {
      using var fileLocalPath = File.Create(writeFullPath);
      {
          fileSteam.CopyTo(fileLocalPath);
          fileSteam.Dispose();
      }
   }

   string readFullPath = Environment.CurrentDirectory + @"\wwwroot\Files\" + fileName;

  // Add File Stream to Content
  var fileSteamLocalFile = new StreamContent(File.OpenRead(readFullPath));
  content.Add(fileSteamLocalFile, "file", fileName);
                   
  content.Add(new StringContent(uploadResponse.uuid), "uuid");

  try
     {
        //Upload File to AWS
        request.Content = content;
        var responseUploadFileMsg = await httpClient.SendAsync(request);
        fileSteamLocalFile.Dispose();

       // Delete temp file 
       if (File.Exists(readFullPath))
       {
          File.Delete(readFullPath);
       }