Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to that.
It seems that you’re currently using the Rank Math PRO plugin, but the account you have used to open this ticket is the Rank Math free version.
Can you please search and forward a receipt from FastSpring.com so we can locate your account and verify it?
Back to the issue, we can see that your sitemap is working properly:

In this case, please try to follow the steps below and see if that works for you:
1. Flush the Sitemap cache by following this video screencast:
https://i.rankmath.com/pipRDp
2. Exclude the Sitemap files of the Rank Math plugin in your caching plugin. The cache could be via a plugin or from the server. For plugins or Cloudflare, please follow this article:
https://rankmath.com/kb/exclude-sitemaps-from-caching/
Once done, clear your website cache and resubmit the /sitemap_index.xml
in the Search Console.
Let us know how it goes. Looking forward to helping you.
Thank 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.