Main page deindexed by google.

[ctam]

3 days ago our main page('/') has stopped appear in google results. Rest of pages works fine. Even our main page from canadian version of site with similar content works fine. Some times canadian page appears for key word where we had our com version before. But I think this is just result of disappearing com version. Any suggestion were to look? Messages box in google webmastertools is empty. Could this be the question too long page title?

PS: Does any way exist to check if we were punished by Google and reason of this?

For Bing and Yahoo everything works fine.

PPS: We have just found that "cache:our_site.com" and "info:our_site.com" returns in google our_site.ca. So this should be reason of problem. So now we are looking how to fix this.

[KeriMorgret]

I'd look at the source code to see if a robots noindex got added, or if there's a weird canonical tag in the source. If you can't share your URL publicly, consider using a private question credit -- the private questions are not indexed, and only viewable by staff and associates (and we're all under NDAs).