Hello,
Thank you for reaching out. We are sorry to hear that you are facing an issue with creating new redirections.
Can you confirm if this happens only when you choose the ‘301 Permanent Move’ or are you getting this behavior when trying to create other redirection types too?
Also can you please try replicating the issue with a default theme activated and only the Rank Math plugin installed? Let me know if you’re getting the same results – if not, then there is a plugin conflicting with Rank Math. Learn more about performing this check: https://rankmath.com/kb/check-plugin-conflicts/
You might also have a database issue that is preventing the redirections table from being created. To fix this, go to Rank Math > Status & Tools > Database Tools and click on Recreate Missing Database Tables button.

You can also refer to this tutorial for more details on how to set up redirections with Rank Math: https://rankmath.com/kb/setting-up-redirections/
Please try these steps and see if they resolve your issue. If not, you might have to provide us with a temporal login to check this for you.
Looking forward to helping you.
Hello
Thank you for helping. The problem was solved, but I’m not sure if it was because of the actions you suggested.
Nevertheless, the redirection is currently working and I have already created 5-6 rules.
The error occurred when I selected 301 and 410 codes. I did everything by default. I wrote only Source and Destination URLs.
I fix this by that way: “go to Rank Math > Status & Tools > Database Tools and click on Recreate Missing Database Tables button.” – and after I go to REDIRECTIONS and I saw there the rule that I tried to create the day before.
Hello,
Thank you for the update.
We’re super happy that creating the missing database tables on your site fixed the 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.