Why did the site disappear from the issuance of Google?

Question

Google

Hello!
There is a website, it has a lot of pages. Tonight the site was excluded from the issuance of Google.
Not 1 page except the main one is no longer displayed. No methods of the left for promotion were accepted, robots.txt is normal. The site was promoted only by content.
How could this happen, what could be the problem for Google to stupidly take and delete the annual website without warning?

Answer 1

What does Google Webmasters say?
content "a lot of pages", I suppose, did you yourself write at night by thousands of rewriters? or parsanuli with a translator?