Hi @valentina1795
Upon checking your sitemap index (https://www.ubki.ua/sitemap_index.xml), we see that the sub-sitemaps do seem to be loading under http instead of https.
Can you please try resetting our indexables in the database tables by following the steps below?
1. Install & activate the Yoast Test Helper plugin
2. Go to Tools > Yoast Test
3. Locate the Yoast SEO section and click on the ‘Reset indexables tables & migrations’, ‘Reset Prominent words calculation’, and ‘Reset Internal link counter’ buttons. After each click, the page will reload to confirm that each reset was successful. Note: Resetting the optimization doesn’t undo any of the hard work you’ve put into the plugin as the SEO data is also stored in WordPress’ default tables. It’ll just reset the custom Yoast tables that contain the combined data pulled from those default tables.
4. Go to SEO > Tools, and under SEO data, click the “Start SEO data optimization” button to allow Yoast to rescan your content.
Aside from that, please also do try to manually regenerate the sitemap by disabling the sitemap feature, clearing all of your caches, and then reactivating the sitemaps feature and see if that helps – https://yoast.com/help/xml-sitemaps-in-the-wordpress-seo-plugin/
We are going ahead and marking this issue as resolved due to inactivity. If you require any further assistance please create a new issue.
