If you happen to find this when you run “adb devices”
D:\adb devices List of devices attached 0123456789ABCDEF offline
Try this: Look for the file “adbkey.pub” in your computer. It is normally located in %USERPROFILE%\.android. You need to copy this to /data/misc/adb/ as adb_keys. If you have shell access this few lines of code will probably work:
cd %USERPROFILE%\.android adb push adbkey.pub /data/misc/adb/adb_keys
Oh! And remember to reboot the Android system.