TLSharp "invalid checksum! skip"

I'm using TLSharp.dll, the problem is that I can't send any file (small or big). An error I get is - "invalid checksum!skip" at fileResult. There is no problem sending simple text messages... My method is:

  private async static void sendFile(int userID)
    {
        var fileResult = (TLInputFile)await client.UploadFile("1.txt", new StreamReader(Directory.GetCurrentDirectory()+ @"\data\1.txt"));

        await client.SendUploadedDocument(
         new TLInputPeerUser() { UserId = userID },
         fileResult,
         "some txt",
         "application/txt",
         new TLVector<TLAbsDocumentAttribute>()); 

    }

Exception:

System.InvalidOperationException
  HResult=0x80131509
  Message=invalid checksum! skip
  Source=TLSharp.Core
  StackTrace:
   at TLSharp.Core.Network.TcpTransport.<Receieve>d__4.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TLSharp.Core.Network.MtProtoSender.<Receive>d__8.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TLSharp.Core.TelegramClient.<RequestWithDcMigration>d__11.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at TLSharp.Core.TelegramClient.<SendRequestAsync>d__19`1.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TLSharp.Core.Utils.UploadHelper.<UploadFile>d__4.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TLSharp.Core.Utils.UploadHelper.<UploadFile>d__1.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at tlsharp.Program.<getLOG>d__15.MoveNext() in C:\Users\R\source\repos\tlsharp\tlsharp\Program.cs:line 204