Solved! I cannot manage to get the remote for Firestick 4k to connect and override the projectors remote. (therefore no sound control of the projector).

[Kcerf]

The projector is PHILIPS NEOPIX ULTRA. The Firestick otherwise works. Many thanks

 

[americanaudiophile]

The owners manual doesn't mention it so most likely the projector doesn't support CEC which is the protocol that allows control over HDMI.