Maximum number of Site Limit is Reached
|Knowledge Article Number||000233450|
|Description||Force.com Sites can not be deleted once they are created.
|Resolution||If the limit of Force.com Sites has been reached in your org,
you can re-use a deactivated site to house your new Force.com Site pages.
You can choose to delete all or some of the existing pages, to fit your new use case.
If you want to change the domain name, please contact Salesforce Support.