Error: Class "Drupal\simple_sitemap\Controller\SimplesitemapController" not found in include() (line 17 of /var/www/html/web/modules/contrib/domain_simple_sitemap/src/Controller/DomainSimpleSitemapController.php)

I am also facing the same issue on my Drupal 9 site.

"SimplesitemapController" is the old class name; now it's "SimpleSitemapController". As you mentioned, there are a few solutions to this git/windows/mac casing problem over in 💬 Class 'Drupal\simple_sitemap\Queue\SimpleSitemapQueue' not found Fixed . If everything else fails, remove the module completely in all repos and re-download it. I've never experienced this issue (using linux here), but this last resort should fix it.

The error is related to the domain_simple_sitemap module (read the error message carefully). This module is not compatible with 4.x version. See this issue for details ✨ Make compatible with simple_sitemap 4.0 & domain_entity Needs review .

@WalkingDexter Thanks for catching it - you are obviously right.

Automatically closed - issue fixed for 2 weeks with no activity.