What is this all about? What should I do about it?

tanstaafl.

First, check to see if that screen really is from Google, and it's not a pop-up ad (or malware), trying to get you to click on a link to some other site.

If its origin looks legit, then:
https://www.lifewire.com/unusual-traffic-from-computer-network-errors-3968165

I see this sometimes if I visit google from my iphone, on a private page, using apple's private relay. Apparently google doesn't like me being too anon.

You'll get them a lot when running a VPN in particular. And even when you do the verification, sometimes it will still just block you. It appears that is an IP owned by a VPN service.

You may also have issues if your ISP is using CG-NAT i.e. you're effectively sharing the same IP as a bunch of other users.

The link that Tony left suggested that. I haven't received that message again since I turned off the VPN.

I only installed the VPN in order to access one particular site. When I finally got there, it turned out to be a subscription only site that would cost me about the same as I was paying for my whole internet service, so a cost/benefit analysis indicated that not only did I not need that site, I don't need the VPN either. I'm still within the 30-day free trial period of the VPN, so I will cancel it.

Also, now the VPN keeps putting up dire messages that I am about to be overrun by terrorists or something because I am so foolish as to have internet service without that essential VPN "protection" turned on. Apparently dastardly hackers are all waiting in line to compromise my internet connection and find out what my favorite porn sites are or something.

tanstaafl.

Be careful with VPN "apps" and the like -- they can often turn out to be the very trojans they're "warning" you against..

Surfshark VPN is now cancelled, refund pending. Not surprisingly, it was far more difficult to cancel than it was to subscribe, it took a lot of digging through submenus to finally get to where I could connect via chat to a live person. I had made the original purchase through Surfshark's website, and it turned out that since I hadn't purchased the VPN through Google Play or Apple Play, their service bot was totally beyond its pay grade, and God help you if you were connecting through a PC and not a smart phone or a tablet. I spent about an hour taking care of it.

On the plus side, the person I finally connected to on chat was delightful. Since I turned off Surfshark, I have had no more recurrences of the Google warning.

tanstaafl.