Google Map update with WiFi but not with 3G

Question

I've made an app that determines the location (balloon) and shows it on Google Maps (with roads, city etc) so an active internet is needed. This works fine when I'm using WiFi but not on 3G. It determines the location and the location-output tot Google Maps is allright (including a balloon) but the Maps (with road, rivers, city etc) will not update.

Hereby my manifest-settings:

<uses-library android:name="com.google.android.maps" />
</application>  
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
<uses-permission android:name="android.permission.CONTROL_LOCATION_UPDATES" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 1

I solved the problem myself but here's how: After reading several articles on the net it seems some kind of api key error. I read there's a difference in debug-key and signed key so I replaced the debug key with the signed api key and that did the trick.
Why wifi worked and 3G not it's not clear te me and really I don't mind because it all works fine now