Mobile-first indexing. Google first introduced mobile-first indexing back in November 2016 and by December 2018 half of all sites in Google’s search results were from mobile-first indexing. Mobile-first indexing simply means that Google will crawl your site from the eyes of a mobile-browser and use that mobile version for indexing and ranking.
All in on mobile-first indexing. Google is sending out notices now and those notices say “Google expects to apply mobile-first indexing to all websites in the next six to twelve months.
The notices. Clearly Google is trying to be proactive and notify sites that are not yet moved over to mobile-first indexing with specific advice on what those sites need to do to become mobile-first indexing ready.
In this specific case, Kyle said the issue was with “”Missing image” is listed as an error, while “Page quality issue” and “Video issues” are warnings.”
Why we care. If you get one of these notices it is likely a notice you should read and take action on. If Google has issues with accessing your site with the mobile-crawler, then it might impact your indexing and ranking of your web pages in Google.
Information source- Search Engine Land