For a couple of years, I maintained a "mirror" of my blog on a free page hosted in Googlepages. Over the years, people started using links to that mirror instead of the primary site - and the Google bot learned about it, thus offering responses with URLs that pointed to the mirror (ttsiodras.googlepages.com) domain.
After some time, Google announced it would migrate Googlepages to Google Sites, where people wouldn't be able to write their own HTML/CSS/JS, and instead would be forced to use an online editor. I had no desire to spend any effort doing that, so I (a) setup the redirection offered by Google, from the mirror URLs (ttsiodras.googlepages.com/whatever) to the new Google Sites page (https://sites.google.com/site/ttsiodras) and (b) modified my Google Sites page to contain direct links to my main blog page. That way, the "mirror" URLs could still be used to find the content.
And it worked fine. Until now - or at least, until recently.
I checked yesterday, and found out that URLs to the mirror site (ttsiodras.googlepages.com) are now getting 404s, and are not redirected to Google Sites.
Did something change, recently, in the way these redirects work? (I checked some other peoples googlepages and it appears that it's not a "global" thing - they work).
Maybe the redirection was a temporary service offered by Google? If so, I can't understand why - the resources involved in this are surely trivial for someone like Google.
I have already asked on the Google forums, but got no response.
Any hints/suggestions most welcome.