iOS开发:为什么我总是在第一次尝试时出现“连接失败”，而在下一次尝试时却成功了?

I'm using the ASIHTTPRequest lib in my iOS app to make RESTful requests to my Rails 3 web app. I seeing a weird and somewhat consistent error the 1st time I try to make a POST request to my web app, but then the POST request works fine the on the second attempt. The exact error is...I'm using the ASIHTTPRequest lib in my iOS app