When you try to add/edit a location, the "Failure: Forbidden" error can be displayed:
Lack of permissions for the user logged in.
Release : any supported version
You must be logged with "admin" user (not with any other user with administrator permissions) to execute this task.
By default, only the "admin" user has access to DA rest via CA PC proxy url /pc/da/rest.
When you perform this operation logged as "admin" user, you should see this message: