rich test results not showing

rank math description says it will replace your schema plugin. but after using rank math i tested a live page on google rich results test
https://search.google.com/test/rich-results

and it says:
Page not eligible for rich results known by this test
Only a subset of rich result types is currently supported

so why is this.

in the post rank math settings i have set rich snippets data as an article, but its not being picked up. should there not be more data that we need to set like author and publisher or are these auto set by the plugin?

The page I need help with: [log in to see the link]