I think after I solved my problem this could be useful for somebody. There was two problem first my server has configuration problem and server needs restart to free its memory. so it's not bad if you check how memory you are using, and if its possible restart the server.
and after that I have a proxy problem that could be fix with creating a file name app.config and writing this lines:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.net>
<defaultProxy >
</defaultProxy>
</system.net>
</configuration>
Then it'll works fine