We’re sorry to hear you are experiencing this issue on your site.
We looked at the sitemap on your site and see that it isn’t loading from the standard URL of sitemap_index.xml and that URL is returning a 404 error, but that it is loading from the default WordPress permalink of ?sitemap=1.
Google Search Console is likely returning a status of ‘Couldn’t Fetch’ due to the value of the URL submitted being a query string.
A 404 error on your sitemap can be caused by a number of issues, including the permalinks or rewrite rules. As your sitemap is loading from the default WordPress permalink successfully, this would indicate that the issue likely due to the permalinks.
To resolve this, we would first recommend to try resetting the permalink structure in WordPress which can be done by performing the following steps:
? In WordPress, go to Settings>Permalinks
? Clicking ‘Save Changes’ without making any modifications
If you continue to receive the error after resetting the permalinks, we would then also suggest adding a set of rewrite rules to your server and we have a guide on adding these for an Apache servers here: https://yoast.com/help/xml-sitemaps-apache/ and for Nginx servers here: https://yoast.com/help/xml-sitemaps-nginx/.
We also have additional information regarding the sitemap files creating an error here: https://yoast.com/help/my-sitemap-is-giving-a-404-error-what-should-i-do/