阿帕契2.4反向代理首页成功，反向代理二级目录 403 forbidden You don't have permission

Question

目前尝试将我的一个discuz站的其中一个二级目录做反向代理
我在测试的时后，首页可以成功反向代理出去，httpd-vhosts.conf 代码如下:

Include /usr/local/apache/conf/vhost/*.conf
<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot /data/www/default
<Directory /data/www/default>

SetOutputFilter DEFLATE
Options FollowSymLinks
AllowOverride All
Order Deny,Allow
Require all granted
DirectoryIndex index.php index.html index.htm

</Directory>
</VirtualHost>

<VirtualHost 45.123.xxx.xxx:80>
ServerAdmin jfscou@outlook.com
DocumentRoot /data/www/xxx.com
ServerName 45.123.xxx.xxx
ServerAlias 45.123.xxx.xxx
ProxyPreserveHost On
ProxyPass / http://xxx.com/
ProxyPassReverse / http://xxx.com/
</VirtualHost>

但是当我尝试代理二级目录时，则会出现权限不足 403 错误，连网站首页都开不起来
httpd-vhosts.conf 代码如下:

Include /usr/local/apache/conf/vhost/*.conf
<VirtualHost *:80>
ServerName localhost
ServerAlias localhost
DocumentRoot /data/www/default
<Directory /data/www/default>

SetOutputFilter DEFLATE
Options FollowSymLinks
AllowOverride All
Order Deny,Allow
Require all granted
DirectoryIndex index.php index.html index.htm

</Directory>
</VirtualHost>

<VirtualHost 45.123.xxx.xxx:80>
ServerAdmin jfscou@outlook.com
DocumentRoot /data/www/xxx.com
ServerName 45.123.xxx.xxx
ServerAlias 45.123.xxx.xxx
ProxyPreserveHost On
ProxyPass /2015 http://xxx.com/
ProxyPassReverse /2015 http://xxx.com/
</VirtualHost>

不知道二级目录的反向代理哪里有错误?
还希望大家帮忙指点