Hello, I'm having problems with the function: Sites- Create a Site.

I’m testing the option for letting to the user to create a new site, but getting the error message:
“Permission Denied
Not Found / No Access
The page you are looking for either does not exist, or you do not have the permissions to access it”.
I have enabled in registration setting: Both sites and user accounts can be registered.
What am I missing?
Thank you.