Note: You are currently viewing documentation for Moodle 3.4. Up-to-date documentation for the latest stable version of Moodle is likely available here: error/local hub/freshmoodleregistrationerror2.
You are trying to register a site with a url that was previously used by another registered site. A request to register this url has already been sent to the site administrator of this other site. This administrator (probably you) need to confirm the new registration.