What are you going to do on a deindexed post?

I do have a gaming blog that performs well recently but most of its traffic had been lost after changing its theme. Checking some of the keywords that it usually rank, it can no longer be found on the search. I thought that the Search Engine is just making some re-adjustment but after waiting a couple of months, I think that it will no longer be able to recover its rank.

If you have encountered the same experience, what did you do to fix such problem?

Did you change something else besides your theme?

What platform do you use for your blog?

Are you sure that the posts are deindexed?

Try searching for the posts url in google to make sure that they are deindexed.

Did you change something else besides your theme?

No, I didn't change anything. Just my theme.

What platform do you use for your blog?

Its Wordpress.

Are you sure that the posts are deindexed?

Checking the URL in google as you suggested, using the code 'Site:' it appears to be still indexed. But, searching for the keyword, entire title of the post or some long content from the post, it doesn't show up.

Ok ok, so I don't think that this was caused by the change of your theme. Changing the theme doesn't influence the structure of your site, your links or anything else. Maybe has an impact on on-page SEO. If your previous theme was better SEO optimized than the new one, this could be one reason for your drop in rankings. If your post still appears in google that means it is not deindexed. Where it appears in the rankings, is another thing.

Basically you lost your rankings for that post.
This could be due to:
On-page SEO factors:
- The new theme could not be SEO optimized - what was your previous theme and what theme do you use now?
- Duplicate content - do you use duplicate content?
Off-page SEO factors:
- poor link building, which led to a penalty - over-optimization with specific anchors, links from shitty sites with shitty content?
- competition - negative SEO from competitor?

If you want send me a PM with your site and keywords, and I will check it out and try to help

Another thing that you could do is change back to the old theme and see what happens then. If you get your rankings back then you have found your problem

Actually, the reason why I did change my theme is because I read from a certain article that to improve my ranking, I have to eliminate as many errors on my site through the use of an online checker tool such as the W3C Validator. Checking my site with the old theme brings a hundred errors which makes me decide to change the theme.

After searching for a good theme to replace, I ended up using the Hybrid which is so simple and too easy to edit the script. I made a lot of revisions trying to eliminate all errors until I got the nice green message that my site is completely strict and out of errors.

Duplicate content?

All of my contents are originally written by me. Although, some of my content has been copied by autoblogs that now replaces most of my posts. I do hope that this is not the result of the Panda or Penguin update or I might just do auto blogging Lol.

With regards about off-page optimization, I don't do a lot of link building because I'm just targeting long tail keywords with low competition but of course brings small amount of traffic. I do have a lot of these kind of posts which adds up bringing me a lot of traffic in return.

I think the best thing to do is to PM you my site to help me out investigate the issue. Thanks.