In custom post type,comment_form() not working..?

as follows:

<?php
                    $fields =  array(
                        'author' => '<div class="comment-form-comment form-input grid-1-1"><label for="author">Name</label><span class="required">*</span><input id="author" class="wpcf7-form-control wpcf7-text wpcf7-validates-as-required" name="author" type="text" placeholder="Name" required="required"/></div>',
                        'email'  => '<div class="comment-form-author form-input grid-1-2"><label for="email">Email</label><span class="required">*</span><input id="email" class="wpcf7-form-control wpcf7-text wpcf7-validates-as-required" name="email" type="email" placeholder="E-mail" required="required"/></div>',
                        'phone'  => '<div class="comment-form-email form-input grid-1-2"><div class="wpcf7-form-control-wrap"><input id="phone" class="wpcf7-form-control wpcf7-text wpcf7-validates-as-required" name="phone" type="text" placeholder="Phone" required="required"/></div></div>',
                    );
                    $comments_args = array(
                        'title_reply' => '<h5 class="title">Write a guestbook:</h5>',
                        'class_form' => 'single-form',
                        'title_reply_before' => '',
                        'comment_notes_before' => '',
                        'fields' =>  $fields,
                        'comment_field' => '<div class="comment-form-comment grid-1-1"><label for="comment">Message</label><textarea cols="40" rows="2" name="comment" type="textarea" placeholder="Your message..." required="required"></textarea></div>',
                        'submit_field' => '<div class="grid-1-1">%1$s %2$s</div>',
                        'class_submit' => 'submit',
                        'label_submit' => 'SEND MESSAGE →'
                    );

                    comment_form( $comments_args );
                    ?>

Unfortunately, he did not have any output…