Can't Recieve Messages From Contacts On Msn
 

I'm able to login to my MSN Messenger and see all my buddies, my buddies are able to see that I'm online as well. I can send them messages no problem, but cannot receive them.
Let me explain further. There're actually 2 scenarios. 1) My buddies cannot send my any messages/initiate conversation at all. 2) I'd initiate a conversation, and able to receive messages from my buddies, however, after a few minutes of inactivity, I'd fail to receive any new messages.

I've tried to login using different versions of MSN/Windows Live Messenger on different computers, but same thing happened.

So any solution ?