Please follow the below steps to fix it.
1. Please make sure your USB-C cable supports DisplayPort Alternate Mode.
2. Though the USB-C cable is symmetrical, the different sides of the cable may
have different stability. Please try to plug the USB-C cable upside down or
right side up and wait for 10 seconds. Please try this on the projector and
source device side.
3. Please power cycle the projector
4. If it still cannot work after the above steps, please change to a
USB-IF-certified USB-C cable.