Hello,
Thank you for your query and we are so sorry about the trouble this must have caused.
Please try re-activating your Rank Math PRO plugin. To do that, navigate to your WordPress admin area > Rank Math > Dashboard > Help, disconnect and reconnect your Rank Math account.


After that, head over to WordPress Dashboard → Rank Math → General Settings → Content AI and refresh the credits. Here’s a screenshot for reference:

Once done, please go back to using Content AI and it should work without any issues.
Hope that helps and please do not hesitate to let us know if you need my assistance with anything else.