Hello,
Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.
I’ve checked the page, and its robots meta tag is set to noindex.
If you wanted it to be set to index, please follow the steps in this link:
https://rankmath.com/kb/excluded-by-noindex-tag/#num-1-check-rank-math-metabox
Once done, clear your website’s cache and revalidate the error in your Google Search Console account. Then give Google some time to recrawl your site

I hope that helps.
Thank you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.