XZ271 monitor with a HDMI connection from a hub

A Lenova laptop is plugged into a new USB-C multiport hub which I’ve connected to an Acer XZ271 monitor via a HDMI cable. When I power on the monitor, its power indicator is Blue for a while and it briefly shows “No signal” message before its power indicator goes Amber for around 15 seconds, and then it goes off. Windows 10 on the laptop shows laptop and XZ271 displays but XZ271 disappears temporarily during the Auto Source cycle.

I've repeated this many times (including laptop reboots) with the same result. I’ve tried swapping XZ271 HDMI ports and turning off Auto Source to no avail. However, when I swap the Acer monitor for a Toshiba LCD TV and change its signal source from TV (Aerial) to HDMI, the laptop screen appears and Windows 10 shows laptop and Generic PnP Monitor displays.