WP returns to domain root instead of siteurl

Make sure that mod_rewrite is loaded and enabled. If you’re not sure, there are plenty of resources on the web with tips on how to check if mod_rewrite is working in your environment. If it is enabled, then check to make sure Apache is set up to allow the use of a .htaccess file for your environment – AllowOverride may be set to None (should be set to All).