从Android错误中调用asmx web服务:“java.io。IOException:HTTP请求失败，HTTP状态:500 "

I'm trying to call .asmx web service from Android. Below you can see my code. It's working when I use it for another web service but it doesn't work for one I need to use. The problem is "java.io.IOException:HTTP request failed, HTTP status: 500" exception. Firstly i assume that the problem is from the web service side. However it works when i try to reach using Devexpress and .NET. I'm trying to call .asmx web service from Andro