Hello,
Thank you for contacting the support, and sorry for any inconvenience that might have been caused due to that.
Please ensure that you are installing the latest version of Rank Math Free. You may check our changelog here: https://rankmath.com/changelog/
I noticed that there are missing database tables, please head over to your WordPress Dashboard > Rank Math > Status & Tools > Database Tools, scroll down to Re-create Missing Database Tables and click Re-create Tables

If the issue persists after doing so, we might need to take a closer look at the settings. Please edit the first post on this ticket and include your WordPress & FTP logins in the designated Sensitive Data section.

It is completely secure and only our support staff has access to that section. If you want, you can use the below plugin to generate a temporary login URL to your website and share that with us instead:
https://wordpress.org/plugins/temporary-login-without-password/
You can use the above plugin in conjunction with the WP Security Audit Log to monitor what changes our staff might make on your website (if any):
https://wordpress.org/plugins/wp-security-audit-log/
We really look forward to helping you.
Hello,
Looks like after that rebuild the issues were fixed, thanks!
Hello,
We are super happy that this resolved your issue. If you have any other questions in the future, know that we are here to help you.
If you don’t mind me asking, could you please leave us a review (if you haven’t already) on https://wordpress.org/support/plugin/seo-by-rank-math/reviews/#new-post about your overall experience with Rank Math? We appreciate your time and patience.
If you do have another question in the future, please feel free to create a new forum topic, and it will be our pleasure to assist you again.
Thank you.
Hello,
You’re very welcome, and please don’t hesitate to contact us anytime to assist you with anything else.
Thank you.