Android O Developer Preview emulator always OFFLINE : <p>I'm trying to test my app against the Android O developer preview. I can download and run the emulator, but when deploying my app, it always comes up as "[OFFLINE]". If I go ahead and try to deploy anyway, I get the following output:</p>

<pre><code>com.android.ddmlib.AdbCommandRejectedException: device unauthorized.
This adb server's $ADB_VENDOR_KEYS is not set
Try 'adb kill-server' if that seems wrong.
Otherwise check for a confirmation dialog on your device.
Error while Installing APK
</code></pre>

<p>I've tried restarting ADB as suggested in the output above. Also, I never get a confirmation dialog in the emulator. Emulators for other versions. eg. Nougat 7.1 work fine.</p>

<p>I'm running Android Studio 3.0 Canary 1 (the standard channel doesn't work either). </p>
