Content From One Domain Mysteriously Indexing Under a Different Domain's URL

[andrewv]

I've pulled out all the stops and so far this seems like a very technical issue with either Googlebot or our servers. I highly encourage and appreciate responses from those with knowledge of technical SEO/website problems. First some background info:

Three websites, http://www.americanmuscle.com, m.americanmuscle.com and http://www.extremeterrain.com as well as all of their sub-domains could potentially be involved. AmericanMuscle sells Mustang parts, Extremeterrain is Jeep-only.

Sometime recently, Google has been crawling our americanmuscle.com pages and serving them in the SERPs under an extremeterrain sub-domain, services.extremeterrain.com. You can see for yourself below.

Total # of services.extremeterrain.com pages in Google's index: http://screencast.com/t/Dvqhk1TqBtoK

When you click the cached version of there supposed pages, you see an americanmuscle page (some desktop, some mobile, none of which exist on extremeterrain.com http://screencast.com/t/FkUgz8NGfFe

All of these links give you a 404 when clicked...

Many of these pages I've checked have cached multiple times while still being a 404 link--googlebot apparently has re-crawled many times so this is not a one-time fluke.

The services. sub-domain serves both AM and XT and lives on the same server as our m.americanmuscle website, but answer to different ports.

services.extremeterrain is never used to feed AM data, so why Google is associating the two is a mystery to me.

the mobile americanmuscle website is set to only respond on a different port than services. and only responds to AM mobile sub-domains, not googlebot or any other user-agent.

Any ideas? As one could imagine this is not an ideal scenario for either website.

[TheeDigital]

I'm not sure what would be causing this. It looks like the pages did exist on the services subdomain at one time. Maybe try adding the subdomain in Webmaster tools and removing all pages. You might also want to add a robots.txt to the subdomain and disallow bots from crawling.

[CommT]

A similar thing happened to me once. In my case, the DNS settings were incorrect. Check that