TarquinTheDark wrote:
They could be using https protocol with an expired certificate.
In fact they don't even use an SSL certificate at all, thats why the site is "not secure".
In July 2018 there was the official announcement from Google, that they will even show warn messages, if a site isn't using https encryption. Also sites not using an SSL protocol will get bad rankings in terms of search result listing on Google. See also:
https://security.googleblog.com/2018/02/a-secure-web-is-here-to-stay.html