Readability will stay grey until content is entered for it to score. The plugin must be able to see this content which some visual builders do not allow.
SEO score will stay grey not only until content is entered but until your focus keyword is set. Similar to above, we must be able to see the content to score it.
If you’re using the native WordPress writing boxes, have filled in your content and entered a keyword, and they stay grey, then troubleshooting is needed.
Please start by completing a full conflict check using these specific steps: https://kb.yoast.com/kb/how-to-check-for-plugin-conflicts/
Then, if you still believe you have a bug, you can file a bug report or request features for the Yoast SEO plugin in the following GitHub repository: https://github.com/Yoast/wordpress-seo