Error submitting page to IndexNow.

Hello @central4allgmailcom,

Thank you for contacting the support, and sorry for not following up quickly and for any inconvenience that might have been caused.

That error is related to the following module:
https://rankmath.com/kb/fix-403-forbidden-error-indexnow/
&
https://rankmath.com/kb/how-to-use-indexnow/

If that does not help, please open a new support topic with the main plugin here:
https://www.ads-software.com/support/plugin/seo-by-rank-math/#new-topic-0

Looking forward to helping you.