Has anyone else gotten this message trying to log in after updating to 1.2.4? I can no longer play minecraft online
Go to command prompt (right click and run as admin if you are running Windows Vista/7) and type "ipconfig /flushdns". This might help but not sure.
Have you tried just waiting a while? If you can't play online at all because of it, then it's probably an authentication issue through mojang. If that's the case, I'd wait and see if the lockout resets, and if it doesn't then try contacting mojang's support to see if they can help.