我们公司原来可以上天涯社区（http://main.tianya.cn/），但现在却上不了了，提示如下（英文的）：
Network Access Message: The page cannot be displayed
Explanation: There is a problem with the page you are trying to reach and it cannot be displayed.
Try the following:
Refresh page: Search for the page again by clicking the Refresh button. The timeout may have occurred due to Internet congestion.
Check spelling: Check that you typed the Web page address correctly. The address may have been mistyped.
Access from a link: If there is a link to the page you are looking for, try accessing the page from that link.
If you are still not able to view the requested page, try contacting your administrator or Helpdesk.
Technical Information (for support personnel)
Error Code: 502 Proxy Error. The ISA Server denied the specified Uniform Resource Locator (URL). (12202)
IP Address: **********
Date: 9/18/2006 7:18:21 AM
Server: *******
Source: proxy
由于不太方便，我把IP地址和server改成*号了，想问一下是怎么回事？是因为网站流量过大还是会有病毒而被网管限制了吗？有什么解决的办法吗？谢谢！
參考答案:很明显是被限制了呀