In-App purchase not working with 3G device

I have developed an iPhone application which implements in-App purchase (server model). While testing I came across a very strange problem. I have tested it on Wi-Fi network. The application works fine. All the downloads (using sandbox account), everything is tested successfully.

However, When I tried to download the same product using 3G connection, the error message (from App Store API) is prompted saying "Wifi required. This item can only be downloaded over a wifi connection."

I haven't found anything on the internet related to this problem. I am struck with this problem and trying to solve it since 2 days but still haven't found any solutions. K开发者_如何转开发indly help me out.

Thanks in advance

It's the carriers/providers that impose the download limits, currently at 20MB's, over 3G I guess. So check your size of the downloads also check whether if you added any new network/wi-fi related key in info.plist