Hello,
Thank you for reaching out to us and sorry for any inconvenience that might have caused due to that.
This error normally comes up when another plugin or a theme modifies the sitemap, it is likely that there is some whitespace on your sitemap index arising from an empty space on your functions.php file located on your current theme or any of the plugins.
You can quickly test if this is the case by switching to one of the stock WP themes and check if you can reproduce this issue.
You can follow this troubleshooting guide to check for plugin conflicts as well: https://rankmath.com/kb/check-plugin-conflicts/
Only the site admin would know and your users won’t be affected by this troubleshooting.
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.
