Intermittent monitor and screen blackout

I've been having intermittent blackouts (usually lasting around 5-10 seconds). These are frequent when my Macbook Air is connected to my Acer monitor (5 or 10 times a day). When the blackout occurs, the screen goes black, then it often cycles through messages, showing (in order):

• <VGA plug> in upper right
• <DVI plug> in upper right
• <HDMI plug> in upper right and
• <No Display> in blue box in center.
• Finally the screen comes back on.

Blackouts also occur, but less frequently, when my Macbook Air isn't connected to a monitor. The messages don't display when the monitor isn't connected.

Whether connected to the monitor or in standalone mode, my Macbook Air continues to accept mouse and keyboard commands during the blackout.

I have already researched Apple Support: Has anyone experienced random momentary monitor blackouts since upgrading to 10.13.4?

This didn't provide an answer. Like the user asking this Apple Support question, I think that the problem occurs more frequently when I'm using Chrome, as opposed to a standalone app like Word, Excel or File Manager -- but I'm not sure of this.

Also researched a MacWorld article, https://www.macworld.com/article/3209746/macs/imac-screen-blackout.html , which offered some elaborate fixes that I haven't attempted yet.

I have tried clearing the Chrome history, cookies and cache, but this doesn't seem to help.

My MacBook Air connects to the monitor via a Belkin 4K Mini DisplayPort to HDMI Adapter. It seems like the Acer monitor blacks out less when I keep the adapter fairly flat, but this doesn't eliminate the problem.

System specifications:

Model Name: MacBook Air

Model Identifier: MacBookAir6,2

Processor Name: Intel Core i5

Processor Speed: 1.4 GHz

Number of Processors: 1

Total Number of Cores: 2

L2 Cache (per Core): 256 KB

L3 Cache: 3 MB

Memory: 8 GB

Boot ROM Version: MBA61.0106.B00

SMC Version (system): 2.13f15

Mac OS High Sierra 10.13.4

Acer H236HL Display

Belkin 4K Mini DisplayPort to HDMI Adapter