Google has begun to notify webmasters recently that their pages are not mobile-friendly directly in the search results. Notice «Your page is not mobile-friendly» is displayed in the snippet, it only saw the owner of the site.
Now, webmasters noted that Google displays warnings for pages that are really optimized for mobile devices.
Screenshot of checking in Mobile-Friendly Test:
John Mueller of Google said that the search engine marked the page as not mobile-friendly due to the speed of its download. page load time can make it non-optimized for mobile devices in the eyes of Google. Thus, Google warned webmasters that their sites are inconvenient for the user because of the performance PageSpeed.
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