Hi,
ACER eventually let us know that we needed to connect the monitor, as well as with the HDMI cable we were using, with a USB-C cable also.
This is not mentioned in the manual for this monitor, nor did anyone at ACER support let us know this through lengthy e-mail correspondence with them. It was only when ACER had us return the item to them for testing that they decided to impart that knowledge.
We won't be purchasing ACER products again.
Hope this helps.
Regards
NJ