Hello,
Thank you for contacting Rank Math, and sorry for any inconvenience caused.
As you have already disabled the firewall, you should ask your web host why the files are still showing a 403 error and ask them to whitelist the Rank Math routes.
You can share this link with them:
https://rankmath.com/kb/meta-data-not-saving/#firewall
I hope this helps. Looking forward to helping you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.