大约一个月前i can no longer update any plugins or wordpress core on my website. 当我试图更新网站时，它被打乱了。Jetpack然后在5-8分钟后为我重新激活网站。当它重新上线时，我在管理部分看到：

您的网站出现严重错误。请查看您的站点管理电子邮件收件箱以了解说明。

不幸的是，我没有收到那封电子邮件。因此，没有进一步的信息。

尽管存在这些问题，我可以继续发表文章，网站的其余部分也能如期工作。

我一直在阅读可能存在的问题，并认为这可能与我的webhosts设置（DigitalOcean）和目录权限有关。

我需要看什么来确定目录权限是否是问题所在？或者，让网站这样做可能会有什么问题？

更新：我已经看过error.log 我看到以下几行重复：

[Tue Jan 21 09:15:26.128769 2020] [fcgid:warn] [pid 16817] [client 52.9.128.29:42158] mod_fcgid: stderr: PHP Fatal error:  Uncaught Error: Call to undefined function get_header() in /var/www/clients/client1/web1/web/wp-content/themes/study-circle/index.php:13
[Tue Jan 21 09:15:26.128824 2020] [fcgid:warn] [pid 16817] [client 52.9.128.29:42158] mod_fcgid: stderr: Stack trace:
[Tue Jan 21 09:15:26.128832 2020] [fcgid:warn] [pid 16817] [client 52.9.128.29:42158] mod_fcgid: stderr: #0 {main}
[Tue Jan 21 09:15:26.128837 2020] [fcgid:warn] [pid 16817] [client 52.9.128.29:42158] mod_fcgid: stderr:   thrown in /var/www/clients/client1/web1/web/wp-content/themes/study-circle/index.php on line 13

<?php
/**
 * The template for displaying home page.
 *
 * This is the template that displays all pages by default.
 * Please note that this is the WordPress construct of pages
 * and that other \'pages\' on your WordPress site will use a
 * different template.
 *
 * @package Study Circle
 */

get_header(); 
?>
<div class="container">
     <div class="page_content">
        <section class="site-main">
             <div class="blog-post">
                    <?php
                    if ( have_posts() ) :
                        // Start the Loop.
                        while ( have_posts() ) : the_post();
                            /*
                             * Include the post format-specific template for the content. If you want to
                             * use this in a child theme, then include a file called called content-___.php
                             * (where ___ is the post format) and that will be used instead.
                             */
                            get_template_part( \'content\' );

                        endwhile;
                        // Previous/next post navigation.
                        the_posts_pagination();

                    else :
                        // If no content, include the "No posts found" template.
                         get_template_part( \'no-results\', \'index\' );

                    endif;
                    ?>
                    </div><!-- blog-post -->
             </section>

        <?php get_sidebar();?>     
        <div class="clear"></div>
    </div><!-- site-aligner -->
</div><!-- content -->
<?php get_footer(); ?>

function get_header( $name = null ) {
    /**
     * Fires before the header template file is loaded.
     *
     * @since 2.1.0
     * @since 2.8.0 $name parameter added.
     *
     * @param string|null $name Name of the specific header file to use. null for the default header.
     */
    do_action( \'get_header\', $name );

    $templates = array();
    $name      = (string) $name;
    if ( \'\' !== $name ) {
        $templates[] = "header-{$name}.php";
    }

    $templates[] = \'header.php\';

    locate_template( $templates, true );
}