Google made it so that Chrome would show a site is not secure when there is mixed content. But does that impact how the page ranks in Google search? Not currently.
Mixed content occurs when initial HTML is loaded over a secure HTTPS connection, but other resources (such as images, videos, stylesheets, scripts) are loaded over an insecure HTTP connection. This is called mixed content because both HTTP and HTTPS content are being loaded to display the same page, and the initial request was secure over HTTPS. Modern browsers display warnings about this type of content to indicate to the user that this page contains insecure resources.
Chrome will issue a warning for it and even Google Search Console may send you a notice about the issue.
John Mueller from Google said on Reddit “Yeah, for the most part, it doesn’t change anything. That said, if your pages no longer render completely in a browser, we probably won’t be able to render those parts either. If your pages stop working in a browser, then you need to fix that.”
This was when he was asked if “Does it also affect Google rankings?”
Forum discussion at Reddit.