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.
For troubleshooting, please get in touch with your web host and ensure that the ModSecurity
(ModSec) is disabled or they are not blocking any process of the plugin.
You can also ask them to whitelist Rank Math’s routes for saving:
/wp-json/rankmath/v1/updateMeta
/wp-json/rankmath/v1/saveModule
If the issue still persists, please verify if the redirection tables are created by heading over to WordPress Dashboard > Rank Math > Status & Tools > System Status > Rank Math:

Let us know how this goes.
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.