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.