This is the first error we see, when we set up Hybris and hit http://localhost:9001/
Hybris supports multi sites for a single code base, which can be accessed by passing a request parameter while accessing the site for first time. This parameter is set in browser session for subsequent requests.
When you pass the parameter site, with value same as your CMS site id, you are able to see the home page.
If you are using a single storefront, then you need to tell hybris specifically, by configuring the URL patterns for your site, so that hybris knows, what site you are looking for, when hit without a parameter. This can be dine in site.impex