Because algorithms. It’s not like Google’s employers manually checked this domain as “untrusted”. There is just some bot, who thought that, and we know, that computers are not perfect in such works.
What are your DNS ? Google with 126.96.36.199 ? Use Cloudfare for first DNS : 188.8.131.52, no warning
How to setup correct DNS
Which system? I’m with Linux… If your are with Windows, there are several tutos about it with Google/DuckDuckGo, Qwant…
Im using Microsoft and Google
But Bot’s were trained by Google.
Try this one if your have Windows 10 : https://www.windowscentral.com/how-change-your-pcs-dns-settings-windows-10
Or this one for 7/8/10 : https://gadgets.ndtv.com/internet/features/how-to-change-dns-server-on-windows-7-8-windows-10-and-macos-1669869
Use Cloudfare DNS : 184.108.40.206 and 220.127.116.11 or OpenDNS if you want…