Problem with HDMI to VGA converter

I am trying and failing to use a baolongking HDMI to VGA converter to drive a Dell P1130 21" CRT screen. The screen works fine (I very recently checked it with an old lapttop which then promptly died of it's own accord).

The model number of the converter is 7b772d6c-e4bb-4858-8870-201a61dabae1 and it is an active converter according to Amazon (and I also checked with Gemini and ChatGPT). The CRT just seems to be getting no signal. The machine I'm using is a desktop with a Ryzen 7 CPU (5700X) and an nVidea 4060.

The adapter will easily drive an old Samsung LED panel. I am confused and annoyed. Any help would be very gratefully appreciated. All I need is a photo of the P1130 showing a retro game so I can sell it!