Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to that.
Could you please get in touch with your web host and ensure that the ModSecurity is disabled or they are not blocking any process of the plugin?
Disabling ModSecurity should fix the issue.
Let us know how it goes. Looking forward to helping you.
Thank you.
Hi. Thanks for the suggestion. This has worked perfectly. Your help is greatly appreciated.
Hello,

Thank you for the update.
We are super happy that this issue is already resolved. 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.