Unable to decrypt the file from ftp server C#

IEnumerable<string> files = Directory.EnumerateFiles(@"E:\\Folder1");
			using (WebClient client = new WebClient())
			{
			 client.Credentials = new NetworkCredential("username", "password");
			 	//encrypr datetime.
			 	upload_encryption.AES a = new AES();
			 foreach (string file in files)
		     {	         
				 	FileInfo file1=new FileInfo(file);				 	
				 	a.EncryptFile(file.ToString(),"D:\\test"+file1.Extension,"passwd");
				 	client.UploadFile("ftp://192." + Path.GetFileName(file), "D:\\test"+file1.Extension);	
		           File.Delete("D:\\test"+file1.Extension);
		            FileInfo file2= new FileInfo(file);
		            a.DecryptFile("ftp://192..... ","D:\\test"+file2.Extension,"passwd");
		            client.DownloadFile("ftp://192./"+Path.GetFileName(file),"D:\\test"+file2.Extension);
					//File.Delete("D:\\test"+file2.Extension);		            
	         }
		    }        	 
       	}
        	catch(Exception e)
        	{
        		
        	}