I found this page, but when I tried to view it, after clicking through a Google search to a Google support page, where I passed a captcha just to do the search, I somehow failed the second(!) captcha on visit to the support page, where Google said it detected suspicious activity on my network and wouldn’t let me actually view the page, but maybe it’s enough to get you started on your end? I suspect my VPN host has me lumped in with some noisy neighbors or something.

https://support.google.com/adspolicy/answer/10249050?hl=en

Edit:

The actual error says this:

> This page appears when Google automatically detects requests coming from your computer network which appear to be in violation of the Terms of Service. The block will expire shortly after those requests stop.

> This traffic may have been sent by malicious software, a browser plug-in, or a script that sends automated requests. If you share your network connection, ask your administrator for help — a different computer using the same IP address may be responsible. Learn more

> Sometimes you may see this page if you are using advanced terms that robots are known to use, or sending requests very quickly.

I'm not doing anything like that except maybe the advanced search terms, but I don't know which ones bots use, and I don't use bots, so I can only assume it's the VPN in combination with some of my search terms. The first time I saw it was right after recaptcha failed to load in on mobile, so who knows. I blame Google. When you can't even click on the Learn More link because you get another error, and you have no actual customer support, I think I might call my Congressperson. This is an ADA violation waiting to happen.