Android Beta Program: verification failed I'm trying to install the Android N preview on my Nexus 9 (volantis). I enrolled for the beta program, and immediately got a notification on the device. After the 1GB download, however, the Android Beta Program updater informs me that validation failed.

I tried several times, also on a different WiFi at work. What gives?
It turns out that my Nexus 9 was still running the latest Android M preview.

After snagging the latest Android Marshmallow (6.0.1) build for volantis and flashing it manually (see the instructions here), the OTA update came in again and the Android N preview downloaded, validated and installed correctly.

If you don't get offered the OTA update, make sure that you've enrolled your device for the Android Beta Program here.