Wordpress 永久链接在 Nginx 中不起作用

我正在将我的 wordpress 博客从 Apache 迁移到 Nginx。我已经尝试了多个教程来使永久链接正常工作，但对我来说没有任何效果。我的网站结构是这样的：

main site -> www.localhost.com

wordpress blog -> www.localhost.com/blog

网站在/var/www/html，wordpress安装在/var/www/html/blog

我阅读了多篇文章并观看了多个视频，但似乎没有任何效果。请让我知道我哪里出错了。

我定义了两个服务器块，/etc/nginx/sites-available/default 一个用于主站点，一个用于博客。

# Default server configuration
#
server {
    listen 80 default_server;
    listen [::]:80 default_server;

    # SSL configuration
    #
    # listen 443 ssl default_server;
    # listen [::]:443 ssl default_server;
    #
    # Note: You should disable gzip for SSL traffic.
    # See: https://bugs.debian.org/773332
    #
    # Read up on ssl_ciphers to ensure a secure configuration.
    # See: https://bugs.debian.org/765782
    #
    # Self signed certs generated by the ssl-cert package
    # Don't use them in a production server!
    #
    # include snippets/snakeoil.conf;

    root /var/www/html;

    # Add index.php to the list if you are using PHP
    index index.php index.html index.htm index.nginx-debian.html;

    server_name _;

       charset utf-8;
       error_page 404 /404.php;

       location /article {
         rewrite ^/article.* / redirect;
       }

       #location / {
        # try_files $uri $uri/ /loadpage.php?$args; 
       #}

       location ~ \.html$ {
         try_files $uri /courses/index.php?$args;
       }





    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
    #
    #   # With php7.0-cgi alone:
    #   fastcgi_pass 127.0.0.1:9000;
        # With php7.0-fpm:
        fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
                include fastcgi_params;

    }

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    location ~ /\.ht {
        deny all;
    }
}



server {
    listen 80;
    listen [::]:80;
    root /var/www/html/blog;
    index  index.php index.html index.htm;
    server_name  example.com www.example.com;

    location /blog/ {
    try_files $uri $uri/ /blog/index.php?$args;        
    }


    location ~ \.php$ {
    fastcgi_split_path_info  ^(.+\.php)(/.+)$;
    fastcgi_index            index.php;
 #  fastcgi_pass             unix:/var/run/php/php7.1-fpm.sock; #Ubuntu 17.10
    fastcgi_pass             unix:/var/run/php/php7.0-fpm.sock; #Ubuntu 17.04
    include                  fastcgi_params;
    fastcgi_param   PATH_INFO       $fastcgi_path_info;
    fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }

}