Hi Sally,
It could be due to the settings. To be honest, I am not sure from your screenshot as it only shows a HTTP status which doesn’t have much to do with Rank Math or any other SEO plugin.
The thing you should be checking is index and noindex tag.
Please check the page source of the URLs in questions. Check if there is a “noindex” robots tag in there.
Then, determine if it is a post, a page, a category, or a tag archive.
Once you determine what type of URLs are set to index, check their settings at WordPress Dashboard > Rank Math > Titles & Meta.
https://i.rankmath.com/ApCKiM
Check each tab and ensure the settings are what you want them to be.
Do note that sometimes it is good to have certain links set as noindex. This is true, especially for the “Misc. Pages”, “Authors”, and “Tags”. Ideally, you don’t want them to be indexable because that might create duplicate content issues and dilute down your website’s authority.
If the pages set as noindex are amongst the pages I mentioned above; you can ignore them or make them indexable using the provided options.
If you see noindex only on individual pages or posts, you can check the Advanced Tab of that post/page and select the “Index” option:
https://i.rankmath.com/MhGm7v
I hope that helps, and please do not hesitate to let us know if you need our assistance with anything else.