Please follow the below steps.
1.Update QS02 Android TV dongle-installed apps to the latest versions:
Google Play> Manage apps & games> Updates> Update all
2.Update the Google Home app on your Android smartphone to the latest
version
3.Power cycle the projector
4.We suggest the projector and Android smartphone connect with 5GHz Wi-Fi
to avoid 2.4GHz interference. It is suggested to have 10Mbps Wi-Fi
throughput at minimum.
5.Open the Google Home app on your Android smartphone and start to cast
6.If the problem persists after the above steps, please perform a factory reset
on the QS02 Android TV dongle and repeat the above steps