Emails are not enabled on this instance so PeerTube won't be able to send an email to <x id="START_EMPHASISED_TEXT" ctype="x-em" equiv-text="<em>"/><x id="INTERPOLATION" equiv-text="{{ registration.email }}"/><x id="CLOSE_EMPHASISED_TEXT" ctype="x-em" equiv-text="</em>"/> explaining its registration request has been rejected.