Hello,
Thank you for reaching out to us, and we apologize for the inconvenience you are experiencing with accessing the Content AI tools.
It seems that you have purchased a Content AI plan, but you are unable to access the AI tools. This issue might be related to the need to refresh the credits after the recent revamp of Content AI.
To resolve this, please go to your WordPress Dashboard → Rank Math → General Settings → Content AI and refresh the credits. Here’s a screenshot for reference:

After refreshing the credits, please try accessing the Content AI tools again, and they should work without any issues.
We hope this resolves the issue for you. If you need further assistance, please feel free to let us know.
Sources:
How to Use the Content AI Tools in Rank Math SEO » Rank Math