因以下原因：

一、资源或业务仅限中山大学教职员和学生访问（请在校园网内或通过VPN隧道访问），或

二、资源或业务不在服务时段（请在服务时段访问）。

1. The web page that you are trying to access is ONLY provided for students,faculty and staff of Sun Yat-sen University.

2. The website can ONLY be accessed during restricted hours.