Permission denied. Failed to verify the URL ownership

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.

To fix the issue, please make sure the service account is listed as the Owner of the site in the Search Console.

You can follow the steps illustrated here to solve the issue:
https://rankmath.com/blog/google-indexing-api/#num-6-2-403-permission-denied-failed-to-verify-the-url-ownership

Once done, clear your website’s cache and check again.

Hope that helps.

Thank you.