MAMP 通过修改vhost文件配置虚拟主机，为什么只能一个生效？

我在MAMP(非专业版)对应的apache 的httpd-vhost文件中配置了多个虚拟机，但只能有一个生效.

### 相关代码
<VirtualHost *:80>
    DocumentRoot "/Applications/MAMP/htdocs/crm.com"
    ServerName crm.com
    <Directory "/Applications/MAMP/htdocs/crm.com">
       Options +Indexes +Includes +FollowSymLinks +MultiViews
       AllowOverride All
    </Directory>
</VirtualHost>
<VirtualHost *:80>
    DocumentRoot "/Applications/MAMP/htdocs/lr.com/public"
    ServerName lr.com
    <Directory "/Applications/MAMP/htdocs/lr.com/public">
       Options +Indexes +Includes +FollowSymLinks +MultiViews
       AllowOverride All
    </Directory>
</VirtualHost>