Hello,
We suspect you meant that the readability tab is not working though you are using the latest version of the Yoast SEO and WordPress. We would like some more information:
1. Can you confirm you have the right user permissions? You can check by going to WordPress > Users > Your Name > Yoast SEO settings (may need to scroll down) and confirm that both “disable SEO” and “disable readability” are unchecked
2. Can you confirm that the SEO, Readability, and Insights are all enabled by going to WordPress > SEO > General > Features and checking that SEO, Readability, and Insights are all enabled?
3. Can you confirm that SEO and Readability are enabled on the posts? You can check by going to WordPress > SEO > Search Appearance > Content Types and seeing that the Yoast SEO Meta box says “Show”?
4. Can you confirm that if you go to the post/page and click on Screen Options (in the top right) that all the right options are enabled? If you are using the new Gutenberg editor you will need to click on the dots in the corner and select options. See image: https://pasteboard.co/I0PzCxd.png which highlights how to check this.
This article should help serve as a guide for some of the settings — https://kb.yoast.com/kb/how-to-enable-disable-the-keyword-analysis/.
