Why doesn't next-sitemap work properly with next-auth?

Question

repo: https://github.com/Skolaczk/next-starter

After adding next-auth to my app next-sitemap doesn't generate sitemap properly. The result of building the app before and adding next-auth to the photos. Does anyone have an idea how to fix this?

I tried adding this line to sitemap.config.js:

exclude: ['/api/auth/*']

, but it didn't help.

Sitemap before adding next-auth:

<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<sitemap>
<loc>http://localhost:3000/sitemap-0.xml</loc>
</sitemap>
</sitemapindex>

Sitemap after adding next-auth:

<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> </sitemapindex>

enter image description here

I expect the problem to be solved