This problem has been bugging me for ages and I can\'t seem to fix it or fully localize the source of the problem (although at times I can force it by allowing the phone to Stan
My case is...
Nexus-4, Android version. 4.2.2
Because of Security Enhancements in Android 4.2.2, my device was offline.
Android 4.2.2 introduces secure USB debugging which when enabled ensures only host computers authorized by the user can access the internals of a USB connected device using the ADB tool included with the Android SDK.
Update your SDK, accept the RSA key on your phone.
Here is some references.
http://www.infoq.com/news/2013/02/android-4-2-2
http://www.androidcentral.com/semi-pro-tip-android-422-here-your-android-sdk-might-need-updating