Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to that.
In order to resolve the issue, please head over to your WordPress Dashboard > Rank Math > Titles & Meta > Authors and from there enable the Author Archives:

Hope that helps and please don’t hesitate to let us know if you have any other questions.
Thank you.
It worked. Thanks for the quick update.
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.