edit_css together with unfiltered_html are not allowed at WordPress core by default for WP multisite.
case 'edit_css':
case 'unfiltered_html':
// Disallow unfiltered_html for all users, even admins and super admins.
if ( defined( 'DISALLOW_UNFILTERED_HTML' ) && DISALLOW_UNFILTERED_HTML ) {
$caps[] = 'do_not_allow';
} elseif ( is_multisite() && ! is_super_admin( $user_id ) ) {
$caps[] = 'do_not_allow';
Workaround:
URE Pro should be network enabled.
Go to “Network Admin -> Settings -> User Role Editor -> Multisite” tab and turn ON ‘Enable “unfiltered_html” capability’ checkbox.
