Oops !! My MSN can't log-in

康師傅你又唔洗咁驚住.
以上o既dialogue係好常見o既 (我用MSN 7.5 for windows 都偶然係咁)
呢個可能係你internet connection度出現問題
或者係msn server overload, 導致不能上線

個人建議, check下其他internet application
(例如Internet explorer) 可唔可以正常上網.
如果唔得就應該係MSN果邊有事.

or you can try some Multi-Protocol IM Client, like fire (u can d/l at http://fire.sourceforge.net/)
or Adium (http://www.adiumx.com/)
I once has the same problem as yours (can't connect to MSN thru the MAC version of Messenger),
but I can connect to MSN thru Adium just after close the Messenger...

If you want better function of the MSN client,
then try mercury messenger...