Google Search Console is sending notifications to site owners about errors identified in recent HTTP to HTTPS migrations.
Specifically, the notification alerts site owners about pages that are no longer showing up in Google search because they cannot be found.
The Search Console notification reads:
“Google systems identified that you recently migrated your site from HTTP to HTTPS. Approximately 80% of your HTTP pages that were indexed before migration can no longer be found in either your HTTP or HTTPS site. Therefore, these pages are no longer accessible from Google search. If these pages were moved to your HTTPS site, we encourage you to help us find them and include them in Google Search.”
Alan Bleiweiss shared an example on Twitter:
Ooooh first time seeing this. "Site migration gone wrong" notice. pic.twitter.com/behdjK0myy
— Alan Bleiweiss (@AlanBleiweiss) August 17, 2018
Google’s John Mueller replied, pointing out why these errors usually occur:
A lot of https migration problems come from bad or incomplete migrations, we're trying to help folks when we spot these issues. Hope this kind of heads up is useful!
— John ☆.o(≧▽≦)o.☆ (@JohnMu) August 17, 2018
As another Twitter user more succinctly put it: “Looks like someone needed a web developer with SEO knowledge.”
It’s hard to argue with that statement, considering the example shows that 80% of pages can no longer be found.
Google has stated over and over again that webmasters need to give clear direction when performing this kind of migration.
That means setting up redirects for every single page.
Google will not be able to find the new pages on its own without being told where to find them.
Moreover, Google will not understand that a new page is intended to replace an old page without a directive like rel=canonical or a 301 redirect.
Site migrations rarely go smoothly, so at least Google is now notifying webmasters when it cannot find HTTPS versions of HTTP pages.