Vista - Sending messages to mobile device

When I try to send a message to a specific contact, I get "This message was
not sent because messages can't be sent to this mobile number." I can't
figure out why. I have checked his options in messenger, and he has his
mobile phone listed and checked the box to allow messages. In windows live,
the correct phone number is shown and the test seems to work, i.e. he gets
the 4-digit code. Anyone have this problem? Solutions?

its driving me nutz Glenn...it worked great for the longest time and now for
about the past week same error...

"Glenn" <oldjedi@xxxxxx> wrote in message
news:ONBQyze5IHA.5012@xxxxxx

If you only experience this issue with a small number of contacts, it could be that they blocked you.

If you think this was unintentional, you might send them these instructions for allowing SMS traffic from your account:

http://get.live.com/messenger/mobile