AdbCommandRejectedException in Android Studio

Question

I'm trying to run a project in Android Studio and I keep getting this weird error.

PropertyFetcher: AdbCommandRejectedException getting properties for device 3004a4ebc1303100: device offline
PropertyFetcher: AdbCommandRejectedException getting properties for device 3004a4ebc1303100: device unauthorized.
This adbd's $ADB_VENDOR_KEYS is not set; try 'adb kill-server' if that seems wrong. Otherwise check for a confirmation dialog on your device.

Answer 1

have you checked in DDMS perspective that your device is showing online? Try Resetting adb from the DDMS