ℹ
info HP
Status Brightness is too low
The display screen’s brightness setting might be very low, making it hard to see clearly.
? What Causes This
Luminance scale set too low in the Color Space menu of OSD.
ⓘ What This Means
Increase brightness/luminance through OSD under Color Space > Adjust Luminance option.
Source: page 68 of the official manual
From the manual
This error code appears in:
HP Z27 27 Inch 4K Uhd Display