Last year I purchased an M1 MacBook Pro - my first MacOs device - and love it.  However there's a problem I'm running into.  I'm a corporate trainer so constantly in new rooms hooking up to different projector setups.  There's been a couple of instances now where the projector hasn't recognised my MacBook.

Yesterday I was in a room and connected via the hdmi socket in the wall to the projector system.   My displays setting was showing it recognised the display (although it was recognising Creston equipment and I noticed the projector was Hitachi) but the projector wasn't recognising the MacBook.  one it briefly came up with a tonne of interference and then disappeared again.   I switched out the cable for my personal one I travel with still no dice.  I tried connecting directly to the ceiling mounted projector but that didn't seem to work either.  A windows laptop the client plugged in worked fine.  

I've had a similar problem at another client.  Can anyone give any hints as to what might be going on?