De-Indexed by Google and Yahoo same day-what's wrong?

One of my sites ranks well on page 1 of both google and yahoo.I now html redirect it to another product site ranking number 1 as an affiliate,woke up to see it de-indexed by both google and yahoo the same day.Could anyone tell what is wrong and how to restore it back?

 

maybe your server has problem, or blocked robots on robots.txt file

 

I do not think that is the problem.My server is o.k,I am thinking of the html redirection is the issue.

 

Any reply?

 

First, I would check which pages have been deindexed by checking your http response. You should be receiving a 200 response.

You can use this tool http://www.seoconsultants.com/tools/headers

 

Thanks for this

 

Few of my autoblog got de-indexed and I checked in the link above I got 200 ok. So what would be next thing to do...

 

If that was the only change you made, it would appear it is the problem. Return it the way it was and see what happens.