최신버전의 default 스킨 기준입니다.

FTP 접속해서 /kboard/skin/default/editor.php 파일을 수정해주세요.

<?php if(!is_user_logged_in()):?>
<div class="kboard-attr-row">
    <label class="attr-name" for="kboard-input-member-display"><?php echo __('Author', 'kboard')?></label>
    <div class="attr-value"><input type="text" id="kboard-input-member-display" name="member_display" value="<?php echo $content->member_display?>" placeholder="<?php echo __('Author', 'kboard')?>..."></div>
</div>
<div class="kboard-attr-row">
    <label class="attr-name" for="kboard-input-password"><?php echo __('Password', 'kboard')?></label>
    <div class="attr-value"><input type="password" id="kboard-input-password" name="password" value="<?php echo $content->password?>" placeholder="<?php echo __('Password', 'kboard')?>..."></div>
</div>
<?php endif?>

위 코드를 아래 코드로 교체 해보시겠어요?

<?php if(!is_user_logged_in()):?>
<div class="kboard-attr-row">
    <label class="attr-name" for="kboard-input-member-display"><?php echo __('Author', 'kboard')?></label>
    <div class="attr-value"><input type="text" id="kboard-input-member-display" name="member_display" value="<?php echo $content->member_display?>" placeholder="<?php echo __('Author', 'kboard')?>..."></div>
</div>
<?php endif?>
<div class="kboard-attr-row">
    <label class="attr-name" for="kboard-input-password"><?php echo __('Password', 'kboard')?></label>
    <div class="attr-value"><input type="password" id="kboard-input-password" name="password" value="<?php echo $content->password?>" placeholder="<?php echo __('Password', 'kboard')?>..."></div>
</div>