Unable to block/unblock contacts in MSN Messenger

[Guest Ale]

Whenever I try to either block or unblock a contact by right clicking on it

in the contact list the action won't be performed (the contact still shows in

the same status as before attempting the change). When i right click the

contact in my contact list it says either "unblock" or "block" as if they are

blocked/unblocked but there's no red circle next to their name to say they

are blocked in the first case.When I log out from MSN a sign will pop

displaying the message:"Contact X (the one I tried to block/unblock) cannot

be blocked/unblocked. Please try again later".

Is this a server issue or a problem with my MSN installation? I haven't done

any changes to MSN, it was working fine all these years until this issue

appeared all of a sudden. Any ideas to fix this? Thanks.