Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to that.
Please head over to WordPress Dashboard > Settings > General and make sure there are no mismatches in the WordPress URL and Site URL in those options.

After that, please try disconnecting and reconnecting your Rank Math account to see if this resolves your issue.
If the issue persists, you can try adding the following filter on your website and then try reconnecting to your account again.
add_filter( 'rank_math/registration/do_url_check', '__return_false' );
Here is a guide you can follow to add the filter:
https://rankmath.com/kb/wordpress-hooks-actions-filters/
If that also doesn’t help, please check if the option rank_math_connection_data
exists in the options table. If it exists, we recommend following the steps here to set an encryption key and reconnect once again: https://rankmath.com/kb/fix-automatic-update-unavailable-for-this-plugin/#disable-sensitive-data-encryption
Let us know how that goes. Looking forward to helping 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.