error in google search console

@szalunek What is the URL you are using when submitting the sitemap to Google? Are you trying to submit as http://www.szalunek.com.pl/sitemap_index.xml or as http://server623936.nazwa.pl/wp/sitemap_index.xml ?

If you are trying to submit as http://www.szalunek.com.pl/sitemap_index.xml and the page is being redirected, that is why Google is returning the error.

@szalunek Which URL is redirecting to the homepage?

If the sitemap isn’t loading at the sitemap_index.xml URL, it be caused by a number of issues, including the permalinks or rewrite rules. We would first recommend to try resetting the permalink structure in WordPress which can be done by performing the following steps:

Login to WordPress
Go to Settings>Permalinks
Clicking ‘Save Changes’ without making any modifications

​We also have additional information regarding the sitemap files creating an error here: https://kb.yoast.com/kb/my-sitemap-index-is-giving-a-404-error-what-should-i-do/