Delete the line
/home/barbar84/www/wp-admin/includes
File: network.php

Dòng [273/683]:
__( 'We recommend you change your site domain to %1$s before enabling the network feature. It will still be possible to visit your site using the %3$s prefix with an address like %2$s but any links will not have the %3$s prefix.' ),
Fix

Ấn tiếp tục để Delete và ở lại trang, ấn Delete để Delete và quay về List dòng
Function