Thank you for supporting our product. 

when your  APPLE TV remote control can not control the volume of the projector, you can recover by the following operation:

1. restart APPLE TV and projector.

2. Confirm whether the related function is enabled in APPLE TV:

a. Settings->Remotes and Devices->Control TVs and Receivers :set to on

b. Settings->Remotes and Devices->Volume Control :set to Auto mode

3. Turn on all cec-related switches in All settings->Channels & Inputs->inputs- in the projector.

4. whether HDMI2 is connected to ARC, due to part of the protocol conflict, it will cause apple tv remote control not controllable device volume.

If you have any other questions, please don't hesitate to contact Nebula Customer Support at service@soundcore.com  for further assistance.