500内部服务器错误Apache2打开pdf文件时

我正在使用cgi技术做一个简单的网站。我创建了一个域名'www.myexamp.com'。我已经给我的配置我的网站。

<VirtualHost *:80>
        # The ServerName directive sets the request scheme, hostname and port that
        # the server uses to identify itself. This is used when creating
        # redirection URLs. In the context of virtual hosts, the ServerName
        # specifies what hostname must appear in the request's Host: header to
        # match this virtual host. For the default virtual host (this file) this
        # value is not decisive as it is used as a last resort host regardless.
        # However, you must set it for any further virtual host explicitly.
        #ServerName www.example.com

        ServerName      www.myexamp.com
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/myexamp

        # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
        # error, crit, alert, emerg.
        # It is also possible to configure the loglevel for particular
        # modules, e.g.
        #LogLevel info ssl:warn

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

        # For most configuration files from conf-available/, which are
        # enabled or disabled at a global level, it is possible to
        # include a line for only one particular virtual host. For example the
        # following line enables the CGI configuration for this host only
        # after it has been globally disabled with "a2disconf".
        #Include conf-available/serve-cgi-bin.conf
        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
        <Directory "/usr/lib/cgi-bin">
             AllowOverride None
             Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
             Require all granted
        </Directory>
</VirtualHost>

好的。我可以使用域名“ www.myexamp.com”访问cgi文件。例如，当我键入URL作为'www.myexamp.com/cgi-bin/hello.cgi'时。它给出正确的结果。但是，当我尝试打开一些pdf文件（'www.myexamp.com/cgi-bin/test.pdf'）时，它给了我，

500内部服务器错误内部服务器错误

服务器遇到内部错误或配置错误，无法完成您的请求。

请通过webmaster @ localhost与服务器管理员联系，以告知他们该错误发生的时间以及您在此错误发生之前执行的操作。

服务器错误日志中可能会提供有关此错误的更多信息。网址为www.myexamp.com的Apache / 2.4.7（Ubuntu）服务器端口80

我应该将我的站点配置文件配置为读取pdf吗？文件？