My App works over WiFi. But not over 3G in android? Any Guesses?

I have developed an App that target version is 4 (Android 1.6) upto 7 (Android 2.1). I tested this app on the dev phone 2 (Google-Io-Device 1.6 version). I am doing some xml parsing stuff through Internet. i set the <uses-permission> on my Manifest. it works fine in WI-FI Network. Bu开发者_如何学运维t its not working in the Motorola Droid 2.1 with 3G Network. Is there any more specific stuff to do for 3G network? Any Idea?

Thanks in advance.

Edit:

My App works over WiFi Network. But not over 3G Network. Any Guesses?

Only android.permission.INTERNET. It's most likely that the server you're connecting to is only accessible from your local network, if it's behind a router/firewall. An easy test is to try to open the same URL you're trying to hit in the system Browser app.

It'd also be helpful to see the traceback from logcat.