page-sitemap.xml is empty

Hi,

Site Index was created by Yoast SEO plugin.

I have a problem with page-sitemap.xml It exist but looks like is empty.
Google Search Console showing error “Site index looks like HTML”.
When go to https://tatamaran.com.pl/page-sitemap.xml root page https://tatamaran.com.pl/ is opened instead of list of page URLs.
Adding new page to website change date of page-sitemap.xml to today 2021/09/09) but index have the same problems still.
When delete this new page, date of page-sitemap.xml returns to 2021-08-22

e-landing-page-sitemap.xml contains 0 URLs

I will be grateful for a hint as to what may be the reason

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