Sitemap 404ing for multisites

I’m working on a client’s website who has a multisite setup for their two locations, AUS and USA.

They have the bare domain, which is the landing page for the : aspree.org
The AUS website : aspree.org/aus
The USA website : aspree.org/usa

I’m trying to configure a sitemap using the The SEO Framework but I can’t work out how to configure them.

I seem to only have a sitemap for the landing page, which is just the one page: https://aspree.org/sitemap_index.xml

For the AUS and the USA versions, I’m getting a 404

https://aspree.org/aus/sitemap_index.xml
and also tried with https://aspree.org/aus/sitemap.xml

Even though the settings for sitemap are configured for all three sites.

Any thoughts?

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