每当我/任何用户遇到错误页面时，这都会显示：
Fatal error: Uncaught Error: Call to undefined function mysql_real_escape_string() in /home/exampdte/public_html/wp-content/plugins/permalink-finder_bak/includes/pf-404.php:621
Stack trace:
#0 /home/exampdte/public_html/wp-content/plugins/permalink-finder_bak/includes/pf-404.php(428): kpg_find_permalink_post_exact('expected-questi...', '2', 'N', 'N', 'N')
#1 /home/exampdte/public_html/wp-content/plugins/permalink-finder_bak/permalink-finder.php(37): kpg_permalink_fixer()
#2 /home/exampdte/public_html/wp-includes/class-wp-hook.php(286): kpg_permalink_finder('')
#3 /home/exampdte/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#4 /home/exampdte/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#5 /home/exampdte/public_html/wp-includes/template-loader.php(12): do_action('template_redire...')
#6 /home/exampdte/public_html/wp-blog-header.php(19): require_once('/home/exampdte/...')
#7 /home/exampdte/public_html/index.php(17): require('/home/exampdte/...')
#8 {main} thrown in /home/exampdte/public_html/wp-content/plugins/permalink-finder_bak/includes/pf-404.php on line 621
如果您查看错误消息，它会告诉您到底发生了什么，让我们分解它：
Fatal error: Uncaught Error: Call to undefined function mysql_real_escape_string()
这意味着你得到致命错误（因此当前请求将在此处死亡/停止），致命错误是undefined function mysql_real_escape_string()，这意味着该功能不存在。
在Stack Trace中你可以看到/home/exampdte/public_html/wp-content/plugins/permalink-finder_bak/includes/pf-404.php:621，这意味着这是621行上该文件的问题。
mysql_real_escape_string()（和其他mysql_函数）已被弃用，并替换为mysqli_real_escape_string()和相关的mysqli_函数。
所以你要么有一个过时版本的permalink-finder_bak插件，要么你需要停止它，如果他们停止维护它。