Hello wordpress experts

I m facing problem in my wordpress site categories. it's not indexing in Google and other search engine whereas my site is 90 days old and site posts are indexing in Google and other search engine very well . I did some changing in theme colors and menu but i don't think so it's contacted with this problem. I m using these plugin, All In One SEO Pack, Add Meta Tags, Google Xml 3.6.2Site Map Generator.

Don't know what to do m really confused Plz help me to resolve this problem and also recommend me some great plugin for wordpress site.

You Recommendation will be appreciated <3