Hello,
Thank you for contacting us and sorry for any inconvenience that might have been caused due to that.
Could you please share your sitemap URL with us so that we can check the issue further for you?
Meanwhile, you can try to follow the steps from this URL and see if that works for you: https://rankmath.com/kb/couldnt-fetch-error-google-search-console/
Let us know how it goes. Looking forward to helping you.
Thank you.
https://juwa.cc/sitemap_index.xml
here is the site map of my website
Hello,
We have checked your sitemap. It is working and validating without any issues as shown in the image below:

Please clear the cache of your site & server and remove the previously submitted sitemap, then resubmit the sitemap again.
If the issue persists, please click on the main sitemap index in your GSC account and share the screenshot of the error you see there. You can use a tool like https://imgur.com/ to share the screenshots.
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.