we also use Yoast SEO together with Polylang, and we seem to have the same issue with multiple domains/country sitemaps. We only get the “main” language sitemap.
Our structure is a wordpress site with Polylang installed, and 4 country enabled. But Yoast SEO sitemap only outputs one of them.
Setting in Polylang:
The language is set from different domains (checked)
Dansk – https://staging-productsearch.interactives.dk
Svensk – https://staging-productsearch-se.interactives.dk
Norsk – https://staging-productsearch-no.interactives.dk
Soumi – https://staging-productsearch-fi.interactives.dk
The only sitemap accessible through Yoast SEO as i can see it, is:
https://staging-productsearch.interactives.dk/sitemap_index.xml (working)
https://staging-productsearch-se.interactives.dk/sitemap_index.xml (not working)
https://staging-productsearch-no.interactives.dk/sitemap_index.xml (not working)
https://staging-productsearch-fi.interactives.dk/sitemap_index.xml (not working)
Am i doing it wrong or do you guys have a suggestion? Maybe someone can post a direction?