Case-tocase basis. In my case, I came across that I cannot send/received email—Msoutlook 2007; it works the following:
1. Disable the Proxy: Open Internet Explorer, Tools, Internet Options, connection tab, LAN settings, and UNCHECK Proxy Server.
2. Change DNS Address: Right Click, My Network Places icon on your desktop, Click Properties, Right Click Local Area Connection, click properties, under General Tab Double Click Internet Protocol (TCP/IP) then down, under use the following DNS server address, change it, but you have to obtain them from your IT/Administrator
It works for me.