There seems to be some problem at your ISP end since I just checked it myself and it is working perfectly fine for me.... Regards, RightMan
yes i have two accounts one work perfect and other show me this stupid message alot of people around the world have the same problem check yahoo answers
Only happen on certain country, my is OK and now i'm inside the yahoo mail Yahoo answer also no problem, just answer one of the question
some accounts are not working because of the maintenance http://www.ymessengerblog.com/blog/2009/03/13/yahoo-mail-maintenance-tonight/
This had happened to me for one of my yahoo accounts but when i`ve logged in the other account it was working perfect.